Heal Your Brain: How Your Gut Secretly Controls Your Brain Health - Dietitian Sophie Medlin

1. 0:00 – 1:46

   Intro

   1. SMSophie Medlin0:00

      If your gut is not quite working optimally, even though you might not have any specific symptoms, it can still have an impact on your mental health and your mental performance. When people are busy, and they're working too hard, and they're doing a side hustle, and everything else is high pressure, people tend to make their diet quite small, so they might end up eating the same types of foods on repeat, and inevitably those ways of eating have an impact on your gut health, whether you feel it in your gut or not.

   2. AAAli Abdaal0:22

      This episode is an interview with one of the UK's leading experts on gut health. Her name is Sophie Medlin, and she is a dietician. She's also the chair of the British Dietetic Association for London, and she works as a lecturer at King's College London, and is actually also on TV these days as an expert for Channel 4 show which is all about the science of the gut. Anyway, I learned so much in this episode, and you're gonna learn so much as well about the gut, and about healthy nutrition, and about what are all the myths around things like seed oils, and should you eat carbs, and is fried food bad for you, and what are the things that we can do to help improve our gut health, and how the gut-brain axis works, and how, like, our gut health contributes to all of the other aspects of our life.

   3. SMSophie Medlin0:57

      Inevitably, if it's not happy, it's gonna be screaming at your brain all the time, and that is noisy and difficult for your brain to cope with, and that can lead to things like brain fog and struggling with focus and concentration, for example. Similarly, if your gut isn't happy, but you don't really know from other symptoms, but you're getting loads of bugs, infections, viruses all the time, you notice you're really susceptible, that's a good time to start looking at your gut health. And I think, I guess, for this audience, what's really important to recognize is this connection between your gut and your brain, and how they are constantly communicating with each other, for better or worse.

   4. AAAli Abdaal1:27

      At the moment, according to YouTube analytics, 81% of you who are watching this on YouTube have not yet hit the subscribe button. And so if you're, for example, in the now 81% of people who are watching this on YouTube but who are not subscribed to the channel, I would love it if you could do so, and it would be awesome to get that number down to 50%, and it would be cool to get, like, 50/50 sub/non-sub ratio, just, just for

2. 1:46 – 6:36

   How you became a dietician and gut expert

   1. AAAli Abdaal1:46

      fun. Sophie, thank you so much for joining us.

   2. SMSophie Medlin1:48

      Thanks for having me.

   3. AAAli Abdaal1:49

      This will be fun. You're an expert on gut health.

   4. SMSophie Medlin1:51

      I am, yeah. I'm the poo expert. [laughs]

   5. AAAli Abdaal1:52

      The poo expert, yeah, and you've been on TV talking about poo, and I would love to talk about poo and everything about the gut. But I guess, as a starting point, how did, how did we get here? How did you come to become the gut expert? What's kind of a blitz of your life story?

   6. SMSophie Medlin2:05

      Yeah, great question. So I was a weird 15-year-old child that knew I wanted to be a dietician, so I was very lucky to kind of have this direction from a very young age. I was studying catering at GCSE, and I had a catering teacher who was a nutritionist, and we did some stuff on, like, celiac disease and adapting diets a little bit, and I thought, "Yeah, I think that's something I might like to do." So I did a little bit of reading and thought, "Well, I could be a nutritionist," which is a bit quicker to train to do, but that won't necessarily open up all the doors to me. And then I read about being a dietician, knowing that I could then go and work in the NHS and do all sorts of other things within the world of nutrition. I thought, "Well, I might as well keep all the doors open." And at this point I was predicted Ds and Es and Us in my GCSEs, [laughs] so I thought, "I better do some work and make sure I get the grades I need to get into university." But it was a really, really good motivator, um, and I managed to turn that all around and get, got good enough grades to get in, and, uh, yeah, studied nutrition and dietetics, and the story starts from there. Most dieticians start working in the NHS, and that's what I did. So I was in the NHS for about eight years. I did some interesting stuff in elderly medicine, where you get really good at kind of understanding about nutrition support, which is basically supporting undernutrition, so malnutrition, doing lots of tube feeding, making difficult decisions about whether people should be tube fed or whether that's the best thing for them or not, given it might be the end of their life, that sort of thing. Um, I then did head and neck cancer, where you look after people who have all kinds of horrific tumors in their mouth and their throat and all sorts of different places, where obviously eating is massively compromised, and at that same time I was, uh, doing a split role with intestinal failure. And then I went on to do a full-time intestinal failure role, um, where I was, you know, just super inspired by amazing colorectal surgeons doing incredible things, amazing specialist nurses, stoma nurses, people who were just turning people's lives around, and people who were in their most sort of vulnerable moments of their life. Um, and nutrition has a massive impact on what comes out your bottom, right? What you put in the top end has an impact on what comes out the bottom, and when you've had any kind of bowel surgery or you are suffering in terms of your digestion, what you put in has a huge impact, not only on your nutritional status, but also on your q- on your quality of life, so your experience of eating. So if you eat the wrong things, in inverted commas, you're gonna be potentially incontinent and having all sorts of terrible problems that really affect your quality of life and make your life very small. And when I was able to see what a massive difference I could make in that environment to people's quality of life, to their experience of living, to their experience of eating, their relationship with food, I was like, "This is what I want to do forever." [laughs] So I stu- I've stuck with that very much in terms of my clinical expertise. I, uh, was then a lecturer and researcher for five years, most recently at King's College in London, and at that time I was struggling a bit with kind of... I love academia, I love teaching, I love working with students, makes me really happy. I love that kind of mentoring aspect of it. But I was struggling with some of the kind of things that other people found easy, the admin side of things, timetabling, that kind of thing, things that might seem like they don't really matter 'cause you should have admin support, but you just don't in those kinds of environments. And it's things that, you know, upset the students 'cause they don't necessarily know where they're supposed to be. And so I was talking to my mentor, and she was saying, "Look, you know, if you were a student, we'd say to you, 'Why don't you get tested for, like, dyslexia and other conditions like that?'" And I thought, "Well, that's probably a good idea." So I got tested, and I found out that I've got dyslexia, dyspraxia, and ADHD, so full hat trick. [laughs] And at this point in my life, I was trying to make a decision as to whether I wanted to pursue a bit more private practice and see more patients, which I'd continued to do through my academic practice, um, and maybe do some TV work, which I'd started to do a bit of, and work with the media a bit more, and do some consultancy, or whether to do my PhD. And getting that diagnosis made me realize that actually I could torture myself for three years or four years trying to do my PhD, or I could make this decision to focus on the things that I'm naturally good at, the things that I'm Don't find so challenging the things that come to me easily, rather than trying to push in a direction that's always gonna be a difficulty for me. So that's what I did. I quit my job at King's, which was a massive deal. Set up the business a kind of couple of years before that. Did two, both at the same time for a long time, which was far too much. Um, but yeah, I've been running my clinic business called City Dieticians for about four years now, uh, um, outside of King's, and I've got a team of 10 or 11, maybe even 12 dieticians now all with our own specialties. I also run a consultancy company where we design vitamins and probiotic products for, for different companies, and yeah, do some TV work, media work, things like this.

   7. AAAli Abdaal6:29

      Fantastic. That's, like, the most coherent kind of answer to that question I've ever heard.

   8. SMSophie Medlin6:33

      [laughs] It's long though, right?

   9. AAAli Abdaal6:34

      Like, watching your story. Yeah, it's, it's great. Like, you've

3. 6:36 – 9:19

   What is a dietician?

   1. AAAli Abdaal6:36

      clearly had practice in front of a camera. Um, what is a dietician?

   2. SMSophie Medlin6:39

      Yeah, great question. Lovely place to start. So a, a dietician is like the, we're like the medical nutrition people, is what I would usually say. So if you have a medical problem that you want advice on in terms of your diet, you need a dietician. Only a dietician in the UK. You wouldn't wanna see a nutritionist for that. Nutritionists aren't medically trained. You wouldn't wanna see a nutritional therapist. They're much more on the alternative therapy spectrum. So dieticians are the medical nutrition people. We're the only people who are allowed to work in hospitals, in the NHS, that kind of stuff. Um, nutritionists are basically there to help healthy people get healthier, so they're amazing at public health, incredible at research, but really important to remember that anyone can call themselves a nutritionist. So in this country, nu- the term nutritionist isn't regulated, which means that there are some people who have just done a quick, you know, 30 pound nutritionist, I don't know, training course online, and now are calling themselves a nutritionist. You have to be a little bit careful with the credentials of a nutritionist that you're taking advice from, but that doesn't mean to say there aren't incredible nutritionists out there doing amazing work in lots of different areas. So I don't mean to diminish them as colleagues. They just do a different job to us.

   3. AAAli Abdaal7:42

      Yeah. And so what sort of medical training do you have as a dietician?

   4. SMSophie Medlin7:46

      A bit like if you think about a physiotherapist, you would say, okay, so a physiotherapist is different to, like, a massage therapist or a sports therapist. They're qualified people who've gone in and done placements in hospitals and worked alongside doctors and nurses to learn their trade. That's the same as dieticians. So we do three long placements as part of our university training, uh, where we go into hospitals and learn from other dieticians on the job. And then we are registered with the HCPC, the Health Care Professions Agency, and they help us to regulate everything that we do. So if I do something wrong, I'm accountable, and I can lose my registration like a doctor or a nurse could, unlike other people within the profession, sort of the nutrition profession at, at large, where there's no accountability. So they could say anything at all, and something could go really wrong, and it's not their fault because there's no one regulating them.

   5. AAAli Abdaal8:29

      Nice. Yeah, I think nutrition is one of those things where o- o- occasionally pe- pe- people would ask me, "Hey, you know, y- you're a doctor, therefore, like, what should I do about X, Y, Z?" I'd be like, "That sounds like nutrition." We had, like, two lectures on it-

   6. SMSophie Medlin8:41

      Yeah, yeah

   7. AAAli Abdaal8:41

      ... in the start of first year. No one cared about it ever since then. And the only contact I had with dieticians was, "Oh, we're, we're feeding this patient through a tube. Let's call the dietician and then get them to do some alchemy and tell us what formula to prescribe."

   8. SMSophie Medlin8:55

      [laughs] Yeah.

   9. AAAli Abdaal8:55

      Um, or there would often be cardiac arrest calls downstairs to the di- dieticians 'cause a lot of them would faint in the morning.

   10. SMSophie Medlin9:01

       Yeah. [laughs]

   11. AAAli Abdaal9:02

       [laughs] Um, so I'm, I'm really u- unfamiliar with the nutrition side of, I guess, medicine and life, and also with, I guess, the job of a dietician. But I guess I'm, you know, for, for, for people listening to this who maybe do not have officially diagnosed pr- colorectal problems or bowel problems-

   12. SMSophie Medlin9:17

       Mm-hmm

   13. AAAli Abdaal9:17

       ... or stomas or things like that,

4. 9:19 – 13:11

   The importance of gut health

   1. AAAli Abdaal9:19

      what does a dietician do for a, I guess, normal, healthy person?

   2. SMSophie Medlin9:23

      So dieticians don't get involved very much with normal, healthy people. We're mostly dealing with disease or problems, so most of my patients would have a problem with their bowel. It might not be, like, a diagnosed thing. They might say, "I get this really unpleasant wind, and it's really bothering me," and we can work on that. But generally, people will have a problem before they come and see me. In my kind of public-facing work, I guess we're talking about gut health education and trying to get people to look after their guts so that we don't end up in the situation where they're in my clinic with a physical problem with their bowel or in surgery because of a physical problem with their bowel. So that's where we talk about how we can really optimize gut health, not only for our bowel health, let's call it, but also for our general health, because our gut has a massive impact on our mental health and on our physical health and our risk of loads of different diseases and disorders. And actually, the more we look at gut health, the more we realize that it is, um, impacting every part of our body and every system in our body.

   3. AAAli Abdaal10:14

      How do-- how does gut health impact all the-- like, the, the, the thing that's always struck me whenever I've listened to podcasts where, where they're talking about the gut is that it seems like the gut is kind of this sort of black box. We don't quite know what's going on, but we know that it impacts literally everything. Uh-

   4. SMSophie Medlin10:28

      Sure

   5. AAAli Abdaal10:29

      ... I wonder if you can kind of break open that black box a bit. L- what-- to what extent does the gut impact all, all these things that you've talked about?

   6. SMSophie Medlin10:34

      Yeah, I'd love to. Let's talk about that. So obviously, on a very basic level, your gut is where all of your nutrition is absorbed, and every bit of your body is physically made from the foods that you're eating. So if you imagine your skin is made from proteins and lipids that come from your diet, the things that you're consuming, you're basically just a big walking blob of protein with other bits and pieces floating around in there. So actually, everything that we eat has an impact on the structure and function of the whole of our body. So if your gut, in terms of its general function, isn't great, then we can have real big problems, and these are kind of things fr- potentially even things like gallstones, which are super common, other bits and pieces. Generally, just not consuming a very balanced diet, so then your gut has to work harder for various different things. We're using different pathways. So having a healthy gut is super important to the structure and function of the whole of your body and how it's working. But that's mainly, we're talking about kind of the first bit of the small bowel, so the bowel-- the first bit of the bowel, which is the small bowel, which is meters and meters and meters long, travels into the colon. And in the colon, you've got, like, this amazing ecosystem of bacteria and other microorganisms that are constantly communicating with the rest of our body. And this is the bit that we really have been learning more and more about over the last kind of 30 years or so, but it's really come into the fore now, how our microbiome, so the, the bacteria that live in our colon, are interacting with the rest of our body. And how that works is that- When we eat various different foods, so let's take plant fiber as an example, you eat some fruits and vegetables, they travel-- The bits of it that you can't digest, the bits we can't break down, travel through to our colon, where they're fermented by different species of bacteria, and yeasts, and other types of microorganisms. And in that fermentation process, they produce some gas, and they produce other things, but they pr- really importantly produce some metabolites, some things that interact with our bodies. So things like short-chain fatty acids, for example, butyrate is the sort of strongest researched example that we have. When butyrate is released by probiotic bacteria in the colon, that travels through into the rest of our bloodstream and interacts with the rest of our body. It helps to control inflammation. We've seen incredible work with butyrate production being controlling of the inflammatory cascade as- associated with COVID, for example. So butyrate's controlling inflammation in the body. Other metabolites interact with our immune system, so 70% of our immune cells live in our small-- in our bowel, in our colon, and your gut bacteria are constantly interacting with them. And we also produce 95% of the body's serotonin in the gut, which links to our brain health, our mental health, and how we're feeling. So your gut is constantly interacting with the rest of your body, and it's physically, chemically, and hormonally connected to all the other systems in your body.

   7. AAAli Abdaal13:10

      Wow. That's a lot

5. 13:11 – 15:12

   Transformative experiences in clinic

   1. AAAli Abdaal13:11

      going on.

   2. SMSophie Medlin13:11

      [laughs]

   3. AAAli Abdaal13:12

      Do any patients come to mind, or have you, have you seen any stories where someone has had, like, quote, "bad gut health," and then it's been transformed into good, good gut health and then their whole life has changed? Like, I wonder if you can kinda paint, paint one of those pictures for us.

   4. SMSophie Medlin13:26

      Oh my God, yeah. Every week in clinic, it's transformative for people, and, you know, we've been lucky enough to showcase some of that on the recent Channel four show that I've been on, which I'm sure we'll talk about later. But just, uh, if you imagine somebody who cannot control their stools, so their gut health and potentially their m- rectal muscles, for example, are badly damaged by maybe childbirth or just by the aging process, and so everything that they put in the top end, they're constantly fearing having incontinence, fecal incontinence, in a supermarket, on the bus, wherever they go. And to be clear with you, this isn't just old people. This happens to young people. People of all ages and stages of their life can experience this for all sorts of different reasons. I think that's probably the biggest example of where what I do as a dietician can make the biggest difference. Because if we can help someone to control their bowels, so they're no longer fearing having an accident, that obviously has a huge impact on their quality of life. And it's not just things like that. You know, we can get people out of pain through adjusting their diet. If you've got kind of problems with the structure of your bowel, something like diverticular disease, for example, which is a super common condition, unfortunately, it creates problems with the structure of the bowel, and that can create a great deal of pain when you're eating particular foods. So we can adjust the diet and get people out of physical pain. And often when I'm working with patients who have things like inflammatory bowel disease, I'll say to them, "Look, I can't cure your IBD. I can't cure your Crohn's disease or your ulcerative colitis, but I can probably help you to get out of pain and reduce the symptoms." And for them, that's perfect. That's all they're asking for. They're not looking to me to try and fix the problem. They just want some symptom management that they're not necessarily getting medically. And yeah, those are the sorts of things that we deal with every week in clinic. And I guess IBS is probably the biggest one that we see a lot of, and that is less debilitating for some people. But for some people, it's incredibly debilitating with really painful bloating and, and gas and things like that, which they find very difficult.

   5. AAAli Abdaal15:11

      Damn.

6. 15:12 – 18:38

   Signs and symptoms of when to see a doctor

   1. AAAli Abdaal15:12

      Okay. So let's say, let's say someone's listening to this and they're thinking, "Hmm, maybe I have a problem with my gut, but I'm not really..." Like, what, uh, w- what are the sorts of signs and symptoms that someone who doesn't q- is not, is not diagnosed with, like, inflammatory bowel disease or something might have to make them think, "Huh, maybe I s- I should see a dietician"?

   2. SMSophie Medlin15:32

      Yeah, great question. So I would say what's helpful is to start with what's normal, because we don't talk about poo, right? So people don't know what's normal. And what we found in general is kind of actually people just might live with symptoms that they don't actually have to live with, but they just get used to them, partly because they're embarrassed to talk to anyone about it, but also they've never checked what's normal. So in terms of normal bowel function, we would say that anything between-- So passing stool, anything between three times a day and three times a week is normal. If that changes for you, so for example, you start off being a three times a day person, and suddenly you're a three times a week person, that's when you need to get some help. Something's not quite right there. So we call that a change in bowel habit. And I'm not talking about having diarrhea occasionally because you've eaten something the night before or had too much to drink. I'm talking about it being consistent. So over about a two-week period, if you notice your bowel habits change significantly for you, that's the time to go and get some help. The consistency of your stool is the next thing to think about. So what we're looking for is kind of like a smooth, sausage-shaped poo that holds together when it goes into the toilet itself. So most of the time, that's kind of what we want. Most people will be somewhere either end of that spectrum, fluctuating between the two. So sometimes it's too hard, sometimes it's too soft, and that's okay, as long as kind of your median, your medium range is kind of in that soft, sausage, snake-like poo territory. Um, and then we think about kind of wider symptoms beyond that, so things like urgency, for example. If you notice that you, when you need a poo, you really have to rush, and you are worried about that, and it comes on very suddenly, for example, that's when you could get some help. If you find that your poo is really hard and difficult to pass and you're feeling uncomfortable, or you're developing hemorrhoids or piles, or you're getting anal fissures, so like tears in the bottom, those are things that we could help people with for sure. Um, and then if you think the color of your poo might be a bit funny, it's an interesting thing to talk about, but the color of your poo needs to be like a medium brown color is normal. Occasionally, you might eat loads of sweet potato, and it might be a bit more orange, or you might have a green smoothie, and it might be a bit more green. That's fine. But as an average, if it's kind of a medium brown color, that's great. And we don't want it to actually be ridiculously smelly. So if your poo is like really foul smelling, we would think that maybe you're not absorbing everything from your food, and that's something to look at. Or you might have a really affected microbiome that needs some work. If you've got loads of gas that's really uncomfortable for you and or it's particularly smelly, that's a time that we can do some things to make that better for you. If you've got any abdominal pain at all, really important time to get some help, even if it's that kind of pain that you're thinking Ah, you know, it comes and goes. I think it's probably okay. Definitely go and chat to somebody about that, 'cause there's things that we can do to make it better. So in terms of normal and things that you could get help with, I think that kind of covers the basics of, of what people might be living with and just putting up with, that actually they could get some help with, and that are probably signs that something's not quite right in terms of their gut health.

   3. AAAli Abdaal18:12

      As, as you were describing the snake-like, snake, uh, sausage consistency, I was thinking that my poo was often a lot softer than that, until I started taking the Heights pro- pre- prebiotic probiotic-

   4. SMSophie Medlin18:22

      Heights, yeah

   5. AAAli Abdaal18:22

      ... that tablet thing.

   6. SMSophie Medlin18:23

      Yeah.

   7. AAAli Abdaal18:24

      Uh, and now I'm always surprised that I, oh, this looks like a normal poo.

   8. SMSophie Medlin18:27

      Great.

   9. AAAli Abdaal18:27

      It looks like what I would think a normal poo is. Um, so that's been nice. Um, what if someone feels like they- their poo is normal based on all these

7. 18:38 – 23:54

   The brain-gut connection

   1. AAAli Abdaal18:38

      kind of parameters that we've talked about?

   2. SMSophie Medlin18:40

      Mm-hmm.

   3. AAAli Abdaal18:40

      Is there any reason for someone with normal poo to be thinking about their, like, diet and nutrition in that sense? Like, are there, are there optimizations that healthy people without g- gut problems can make to improve, like, productivity, performance, that kind of thing?

   4. SMSophie Medlin18:54

      Yeah, for sure. So i- if your gut is not quite working optimally, then that can, even though you might not have any specific symptoms, it can still have an impact on your mental health and your mental performance, right? So your gut is such an integral part of your whole body system and ecosystem, and inevitably, if it's not happy, it's gonna be screaming at your brain all the time, and that is noisy and difficult for your brain to cope with, and that can lead to things like brain fog and struggling with focus and concentration, for example. Similarly, if your gut isn't happy, but you don't really know from other symptoms, but you're getting loads of bugs, infections, viruses all the time, you notice you're really susceptible, that's a good time to start looking at your gut health. And I think, I guess, for this audience, what's really important to recognize is this connection between your gut and your brain, and how they are constantly communicating with each other, for better or worse. So there is a very strong line of communication between your gut and your brain, which we refer to as the gut-brain axis. And again, they are chemically connected through neurotransmitters that are produced in the gut. They are hormonally connected by the HPA axis, and they are physically connected by the vagus nerve. And the chattiest organ between your brain and your gut is your gut. Your gut is constantly telling your brain all sorts of different things and throwing messages up that it's got to deal with, and people might think, "Oh, it's your brain, your gut's not really doing anything." But actually, your brain is busy, and it's communicating, and it's a lot through those microbes that live in your colon.

   5. AAAli Abdaal20:11

      Sick. [laughs]

   6. SMSophie Medlin20:12

      [laughs]

   7. AAAli Abdaal20:13

      You're very good at this. [laughs]

   8. SMSophie Medlin20:14

      Thanks. Not my first time. [laughs]

   9. AAAli Abdaal20:15

      Like, you've got that whole, like ... I'm just like, "Wow." Um, so w- what can I do, for example, uh, as a, as a proxy for people listening to this? My poo is fine, once a day, you know, medium brown color, not overly smelly, I think. [laughs] But everyone likes the smell of their own poo, apparently. Um, but obviously I wanna kind of maximize my performance and my focus. And actually, one question we, we get so often from our audience is people struggling to focus.

   10. SMSophie Medlin20:43

       Sure.

   11. AAAli Abdaal20:43

       And I think often people are like, "I, I struggle to focus with my schoolwork or with my," whatever, "web design side hustle. I must have ADHD," as, like, an immediate option.

   12. SMSophie Medlin20:52

       Yeah.

   13. AAAli Abdaal20:52

       But I wonder if there's gut stuff we can do before we get to that point.

   14. SMSophie Medlin20:54

       Yeah, definitely. I mean, your gut health is ... So because your, your gut is constantly communicating with your brain, again, if your gut is not happy, things are communicating differently. But also, you could just not be producing enough serotonin for various different reasons, or your gut might not be sending the right signals up to your brain. So you might have, if we looked at your microbiome, and it's certainly not necessary to do that, we can do this in clinic without testing, but if we looked at your microbiome, we might find that you've just not got enough of these bacteria that are doing this particular important job with brain connection stuff. Um, so what we would suggest then is to really optimize the gut. And you know what happens, Ali, as you know, is when people are busy and they're working too hard and they're doing a side hustle and everything else is high pressure, or they've got a family and everything else, people tend to make their diet quite small, in, not necessarily in terms of volume, but the types of foods that they're eating. So they might end up eating the same types of foods on repeat. What I see is people, there's kind of two camps here, the people who do, like, the meal prep stuff and they eat the same foods five days a week, [laughs] and they think they're being super healthy, eating sweet potato and broccoli every day. Or you have the people who are just living meal to meal, prep, you know, Itsy, wherever they're going every day, the same sorts of things, but just various different places, and nothing's particularly planned or thought through. And inevitably, both of those ways of eating have an impact on your gut health, whether you feel it in your gut or not. So that way of eating limits the types of fibers that your gut bacteria are being fed, and the most important thing for your gut health is that you're eating 30 different plants a week, so trying to eat loads of variety of different types of plants. That includes fruit and veg, but also nuts and whole grains, different types of grains. We're super fixated in this country on, like, oats and wheat, but actually there's so many different types of grains that our gut really benefits from. So when you're busy and you're struggling, and you're eating meal to meal, or you're eating the same foods on repeat, what happens is your gut health, your gut sort of function might not change, but your gut health is inevitably not optimized. And that's when you can have these problems with lack of concentration, focus, energy, getting bugs all the time, that kind of stuff. And really interestingly, your gut bacteria communicate with your hypothalamus, so that bit of your brain that controls things like cortisol production. So really early in your life, your gut bacteria dictate where your sort of HPA axis is set, so how much cortisol you release in, under given circumstances. And we all need some cortisol, right? But we don't want loads and loads of cortisol, because when we've got loads of anxiety and stress all the time, we can really struggle to concentrate and to focus. So we can use our gut bacteria to try and reduce that and make things a little bit better in that department. We can use them and harness their powers to get more serotonin, which helps us with better sleep and concentration and focus and all those important things, those happy hormones. And we can also just try and calm down those messages from our gut to our brain, which are distracting our brain all the time. And your gut bacteria are gonna be saying, "We need more plants," and you're gonna be not reading that properly and giving them more sushi, and that's not quite what they want.

   15. AAAli Abdaal23:36

       Wow. So it s- it sounds like you're saying, and please correct me if this is an oversimplification, that changing up what you eat can have a massive impact on your focus, productivity, performance, happiness.

   16. SMSophie Medlin23:48

       Absolutely.

   17. AAAli Abdaal23:48

       Because all of those things are linked, gut, brain, everything.

   18. SMSophie Medlin23:51

       Yeah, fundamentally. I mean, and proven in amazing research

8. 23:54 – 26:26

   Research on microbiome and mental performance

   1. SMSophie Medlin23:54

      and science, yeah

   2. AAAli Abdaal23:55

      What kind of research has been done on this? I guess I'm, I'm, I'm thinking heal- healthy people rather than people with official gut problems.

   3. SMSophie Medlin24:00

      Yeah, so, uh, the amazing work of John Cryan is a really good place to l- to start looking at this stuff if people are interested, and he's written an amazing book called The Psychobiotic Revolution. So psychobiotics are these gut bacteria that communicate with our brain, so they're the ones that we're particularly interested in when we developed the Heights Smart Probiotic, for example. So work that's been done in that area to start with in rodent models, they used a, a model of an autistic mouse and a model of a non-autistic mouse, so a sociable mouse, and they took the microbiome, so they took a sample and f- and gave the microbiome of the autistic mouse to the sociable mouse, and the sociable mouse starts to show autistic traits. Okay? And when they swap them over, the autistic mouse starts to become a sociable mouse, just because its gut microbiome has changed. So that was the early work that they did, trying to understand how much our gut microbiome has impacted, impacting our mental health, our mental performance, how our brain is working. So similar studies to that have then been replicated in humans, in other places. And to be clear, that autistic spectrum disorder stuff in humans is so complex, and we can't replicate that exactly in humans a- as yet, but there's certainly something going on there, which is what we generally learn from rodent studies. We've also got some great data showing things like increase in production of serotonin when we use particular probiotic species. There's great data showing that using particular probiotic species within treatment diets and things like that, so within treatment within, uh, studies, in controlled studies, improves anxiety, depression, all of these kinds of symptoms. And wider nutrients within this world, if we think about things like Omega-3s and B vitamins, they've been used in place of anxiety and depression medications, SSRIs, that kind of stuff, and they work as effectively in some people some of the time in studies. So we can use all of these things. And a sim- similar work has been done with the two strai- one, two of the strains we use in the Smart Probiotic, in terms of seeing whether they work as effectively as common anti-depression, anti-anxiety medications. And they do, so much so that there's health claims on them in Canada that people can say, "These are definitely shown to improve anxiety and depression." So there's great data. It's y- a young field of research, but it's super exciting and it's very solid research, just showing the, the magic that we can harness from our gut.

   4. AAAli Abdaal26:18

      Nice.

   5. SMSophie Medlin26:18

      [laughs]

   6. AAAli Abdaal26:19

      Um, sweet. So clearly there's a lot going on. Uh, one of the things you said, um, nice actionable takeaway for me and

9. 26:26 – 30:19

   You should eat 30 different plants per week

   1. AAAli Abdaal26:26

      anyone listening to this, 30 different plants a week.

   2. SMSophie Medlin26:28

      I know.

   3. AAAli Abdaal26:28

      That's a lot. [laughs]

   4. SMSophie Medlin26:29

      It sounds like a lot, but actually if you break it down into days, you're looking for about five different plants a day. So what you would say is, like, for example, for breakfast, if you had, like, a multi-grain cereal or a whole grain cereal, you're gonna have loads of different in there, in there. Chuck some seeds in, chuck some nuts in, chuck some dried fruit in. I love freeze-dried berries. Amazing. Chuck some of that stuff in, and actually, you're kind of already there with at least five different plants in there. Then at lunchtime, maybe at, b- between your lunch and your breakfast, you could have a handful of nuts there. Lunchtime, make sure you're having at least a couple of different veg in there, maybe chuck some seeds on top. And then in the afternoon, you wanna have some fruit as a snack. And then in the evening, make sure you're having some veg. Like, actually, if you spread it out like that, it's totally achievable for people, unless you're doing one of these funny restrictive diets that, you know, nobody would recommend anyway.

   5. AAAli Abdaal27:11

      All right, we're just gonna take a quick break from the podcast to introduce our sponsor, which is very excitingly Huel. I have been a paying customer of Huel since 2017, so it's been about six years now that I've been using Huel fairly regularly. I started eating Huel in my fifth year of medical school, and I've been using Huel regularly ever since, because, you know, I like to be productive. I've ... you know, my calendar is filled with a lot of things, and often I don't have the time or don't make the time to have a particularly healthy breakfast or a particularly healthy lunch. My favorite flavor is salted caramel, because for 400 calories, you get 40 grams of protein, which is absolutely insane, and you also get a decent healthy mix of carbohydrates and fiber and fat, along with 26 different vitamins and minerals, which are all very good for the body. There's nine different flavors of this to choose from. My favorite is A, the banana version, and also the salted caramel version. So what I do is I take my two scoops, I put them into my NutriBullet blender-type thing, although you can just use a normal shaker if you want. I mix it up normally with water, but a little bit of milk to add a bit more of a milkshake-like consistency to it, and then I just sip that while I'm on my desk doing my work in the morning, and it ensures that I get a very healthy breakfast in that's nutritionally complete, rather than some high-sugar cereal, which is what I would have defaulted to instead. Also, Huel is ridiculously reasonably priced. Like, a meal for 400 calories comes out to £1.68 per meal, which is super, super cheap compared to what the alternative would be if you were ordering takeout, for example. Anyway, if you like the idea of getting these cheap and healthy and nutritionally complete meals in your diet, then head over to huel.com/deepdive. And if you use that URL, huel.com/deepdive, they will send you a free T-shirt, which are quite nice, and also a free kind of shaker bottle-type thing with your first order. So thank you so much, Huel, for sponsoring this episode. This episode is very kindly brought to you by Trading 212. Now, people ask me all the time for advice about investing, 'cause I've made a bunch of videos about it on the YouTube channel, and my advice for most people is generally invest in broad stock market index funds, which is exactly what you can do completely for free with Trading 212. It's a great app that lets you trade stocks and funds and ETFs and foreign exchange if you really want to. And one of the great things about the app is that if you're new to the world of investing, you can actually invest with fake money. You don't have to put real money in. They've got a practice mode where you invest fake money, and then it actually tracks what the market is doing in real time. So you can see, had I invested £100 into this thing, what would my return have been X weeks or X months further down the line? Once you've got some comfort with that, then it's super easy to deposit money into your Trading 212 account. You can use Apple Pay, like I do initially, or you can use a direct bank transfer. And then once the money is in your Trading 212 account, then you can invest it in basically whatever you want. Now, if you're based in the UK, you might be familiar with the concept of an ISA, which is an individual savings account, which is basically a tax-free wrapper that you can put money in. You can put £20,000 in every year, up to £20,000, and it resets every April, and then all that money can grow, and it's completely tax-free for the rest of your life. And if you wanna sign up for an ISA, you can sign up for one completely for free also on Trading 212. So if you haven't yet filled up your ISA allowance or at least put some money into your ISA for this year, that might be a good step forward. The app also lets you auto invest, which is a great thing, 'cause then you can automatically invest a percentage of your paycheck into the thing every month. And so if you haven't yet started with investing and you wanna give it a go, then you can download the app on the App Store, and if you use the coupon code Ali, A-L-I, at the checkout, that will give you a totally free share worth up to £100. It's available on iPhone and Android, and you can check it out by typing in Trading 212 into your respective App Store. So thank you so much, Trading 212, for sponsoring this episode. Yeah, at the

10. 30:19 – 32:39

    Terrible advice from personal trainers

    1. AAAli Abdaal30:19

       moment I'm trying to do a sort of high protein, low-calorie thing to cut with my health coach and all this kind of stuff.

    2. SMSophie Medlin30:23

       [laughs]

    3. AAAli Abdaal30:24

       But, you know, his, his thing is like, you know, at least for a while let's just try and eat the same thing every day s- broadly so that you know what's coming into your body, and then we can see how that affects your weight, all that kind of stuff.

    4. SMSophie Medlin30:33

       I mean, you can see me cringing, right?

    5. AAAli Abdaal30:34

       Yeah. [laughs]

    6. SMSophie Medlin30:35

       Absolutely terrible advice. So I literally, I've, I've got some content planned for this week around what terrible advice I see from personal trainers.

    7. AAAli Abdaal30:41

       Mm.

    8. SMSophie Medlin30:41

       And I'm sure your guy knows what he's doing in terms of personal training, but the worst things that personal trainers do, there's three things I see them doing regularly to people. One is putting you on the same foods on repeat because you're starving off your essential gut bacteria, and some of those really important gut bacteria are actually protecting you from obesity. So they're working to help you to control your body weight. And so if you're starving them, you're making your life much more difficult in the long run. Secondly, it's like this really low fiber diet typically, and so that's just as a measure of them cutting out carbohydrates. Nobody's looked to check, because they don't know what they don't know, right? No one's checked that there's at least 30 grams of fiber in there, which is what we all need every day for healthy, to, for healthy stools and a healthy bowel. Usually, they're around 16 grams of fiber when we calculate them. It's just half of what we need. Um, and then the other thing is having loads of red meat or loads of animal pro- products generally.

    9. AAAli Abdaal31:29

       [laughs]

    10. SMSophie Medlin31:29

        So the World Cancer Research Fund says we should only have three portions of red meat per week, and that's 500 grams, 350 to 500 grams in total. Otherwise, we're putting ourself at higher-

    11. AAAli Abdaal31:39

        In total?

    12. SMSophie Medlin31:39

        In total. Otherwise-

    13. AAAli Abdaal31:41

        Not like, count three?

    14. SMSophie Medlin31:41

        Not every day, no. [laughs] Like 350 to 500 grams total a week.

    15. AAAli Abdaal31:45

        Got it.

    16. SMSophie Medlin31:45

        Otherwise, we're putting ourselves at higher risk of bowel cancer. And so again, these meal plans that people are given actually are starving your gut bacteria, which puts you at risk of loads of different problems, putting you at higher risk of things like cancer, which nobody wants, and all kinds of other things. But it's, it's not the fault of the personal trainer. It's b- going, circling back to this conversation of nutrition pr- people in the nutrition space giving advice on things they just shouldn't really be giving advice on, right? So if you want nutrition advice and t- tailored specific nutrition advice for you, you need to see, we've got an amazing sports dietician on the team at City Dieticians who can tailor all these things for you and give you a proper tailored plan that, no, that you can actually manage in terms of everything, as opposed to just thinking about that one thing, which is the ac- aesthetics which everyone gets fixated on.

    17. AAAli Abdaal32:27

        Oh, that's handy. I'll book an appointment with her.

    18. SMSophie Medlin32:30

        [laughs]

    19. AAAli Abdaal32:30

        That'll be good. [laughs]

    20. SMSophie Medlin32:31

        [laughs]

    21. AAAli Abdaal32:33

        Um, 30 grams of fiber, what does 30 grams of fiber look like in a diet?

    22. SMSophie Medlin32:37

        Well, it's about half-

    23. AAAli Abdaal32:37

        Like-

    24. SMSophie Medlin32:37

        ... of what the average person's getting.

11. 32:39 – 38:05

    Intermittent fasting

    1. AAAli Abdaal32:39

       Oh.

    2. SMSophie Medlin32:39

       Uh, sorry, no, it's about double what the average person's getting. So most people in England eat less than half of what they actually need in terms of fiber every day. So most people are getting around 15 grams of fiber a day. So we need to make sure we're adding lots of extra things in. Things have happened within the social media space that have made that happen. So for example, people now demonize breakfast cereals, where actually-

    3. AAAli Abdaal32:57

       Yeah

    4. SMSophie Medlin32:57

       ... loads of us got loads of fiber from breakfast cereals every day. Women were mainly dependent on breakfast cereals for iron for a long time, and slightly different now, but actually, we cut these things out because an influencer tells us to, and actually there's consequences for everything that we move around in our diet, right? So thinking about where your sources of fiber are, so we're talking about whole grains, fruits and vegetables, nuts and seeds, that kind of stuff, where are your sources of those in your diet, and could you maximize them? So for example, swapping white rice for whole grain rice is a really great step in the right direction, white rice for whole grain pasta. If you're having, like, mince, for example, so minced beef, add some lentils in there, just bulking up the fiber a little bit. Leave the skin on your vegetables, on root vegetables, that kind of stuff. Leave the skin on. You get a bit more fiber there. Making sure you snack on fruit, those kinds of things. It's basically the stuff that your mum would've told you to do when you were a kid. It's all that stuff we need to do to try and boost our fiber intake, and most people just aren't getting enough.

    5. AAAli Abdaal33:46

       What's the deal with breakfast cereal? My, uh, in, in, uh, my influencer adult understanding is breakfast cereal is bad because lots of sugar, and American advertising companies convinced us that breakfast was the most important meal of the day. That's BS. We should all be intermittent fasting-

    6. SMSophie Medlin34:00

       [laughs]

    7. AAAli Abdaal34:00

       ... and just skipping breakfast in the morning anyway, 'cause 16-8 fasting is good for you, so therefore breakfast cereal is evil. [laughs]

    8. SMSophie Medlin34:06

       Yeah, sure, yeah.

    9. AAAli Abdaal34:06

       What do you think?

    10. SMSophie Medlin34:06

        I mean, I, I hear all those things as well. I think the key thing with breakfast cereal is it can very easily become what we might call an ultra processed food, and that's where it's just got loads of extra additives in it that you wouldn't recognize in your kitchen, preservatives, emulsifiers, that kind of stuff. Uh, lots of extra sugar, salt, all those kinds of things. So we want to avoid those ones. So the ones that look like they're super commercial, we probably wanna push them-

    11. AAAli Abdaal34:26

        Oh

    12. SMSophie Medlin34:26

        ... out the window. But you can add things in, in terms of making your own sort of breakfast cereal. You can toast some oats, toast some stuff to make granola, that kind of stuff. Some of the more natural granolas would be a good choice for you. But in terms of fasting, there's no evidence of any benefits of fasting beyond weight control. So there is some reasonable data to show that fasting can improve weight control, but also there's this counteracting data coming through now where people who don't eat enough in the morning, uh, tend to overcompensate and eat much more in the evening, and that's worse for us from a metabolic perspective. We've kind of got this biological night of around 9:00 PM where all of our processing of everything slows right down, so things can sit around in our bloodstream a lot longer and cause more trouble if we're eating too late at night. So actually, if you're someone who wakes up hungry and you're dragging yourself through till 12 o'clock into your eating window and you're feeling terrible, you've got headaches and you feel awful, that's obviously not the right way for you to be eating. Your body, and we're all different from a circadian rhythm perspective, right? Our body clock is all different. So if you're someone who feels hungry in the morning, you should eat in the morning. Just listen to your body. Be a normal person. [laughs] If you are someone who just doesn't feel very hungry at night, you might find it easier to finish eating at six o'clock, and that might work really well for you. But really importantly, if you're trying intermittent fasting and you notice that you're really loading those calories later in the day, it's probably not right for you. Most studies will show that actually if you have some calories in the morning and front load your calories a little bit, you'll reduce your calories later in the day, which is metabolically a bit better for us.

    13. AAAli Abdaal35:48

        What about things like chicken and fish? What are, like- W- how much chicken and fish should I be eating? [laughs]

    14. SMSophie Medlin35:55

        Great question. So your body, your b- your bowel doesn't particularly like red meat. It certainly doesn't like processed meat, so the, the data on processed meat says little, if any, processed meat for protection of bowel cancer. So processed meat would be things like sausages, bacon, even things like cured meats, that kind of stuff, is just not great for our bowel health. Um, any animal meat, any, any animal proteins, our body, our bowel can quickly find that too much. So a good example that people might recognize is if you ate, like, a meat feast pizza or, like, had a massively heavy, meaty meal, usually your gas the next day or later that evening is gonna be pretty foul smelling, and that's because when we have too much animal protein in particular, it then-- some of that leftover protein that we can't absorb and then digest is being fermented by really bad types of bacteria. They're really not good guys that we don't wanna be feeding, and when they ferment stuff, they release methane and sulfur and these bad-smelling gases. So if you're having really foul-smelling wind, the chances are you might be overfeeding those guys that don't-- you, we don't wanna be feeding them too much, so we can help to balance that out clinically in, in-- with treatment. Um, so excess protein from any source, excess animal protein from any source, is not ideal for people. So your gut health, your gut bacteria also really like plant protein, so things like soya and tofu, that kind of thing. So ultimately, it's about getting that balance right, and if you're someone who is having meat for lunch, like, twice a day, you're probably having too much meat.

    15. AAAli Abdaal37:19

        Hmm. Damn. Okay. [laughs]

    16. SMSophie Medlin37:21

        [laughs]

    17. AAAli Abdaal37:21

        Um, how, how do I get my protein, if not from meat?

    18. SMSophie Medlin37:26

        Great question. So you can use plant sources of protein, so, like, tofu, soya products, that kind of stuff, and obviously we want it to also not be ultra-processed. So I'm not talking about that Beyond Meat burger or that highly processed vegan product.

    19. AAAli Abdaal37:38

        [laughs]

    20. SMSophie Medlin37:38

        What I'm talking about is adding tofu to your stir-fry, for example, using the minimally processed soya mince in place of beef mince, for example. Still great sources of protein for you and absolutely no harm. Eggs are slightly less, um, dramatic in terms of your bowel function than, uh, meat is, so a bit easier for you to digest, and fish is even better. So if you're having fish regularly, that's great for you in terms of protein source. Also great for your brain. Lots of benefits to having fish a bit more regularly than meat.

    21. AAAli Abdaal38:04

        What

12. 38:05 – 39:42

    The importance of fish for brain health

    1. AAAli Abdaal38:05

       are the benefits of fish?

    2. SMSophie Medlin38:06

       Fish is magical. [laughs] We've all kind of evolved to need a lot of fish in our diet, and in England, we just-- like, nobody eats the two portions of oily fish a week that was recommended, right? If we did, the supermarkets would be sold out tomorrow. We need two portions of oily fish a week for our brain health. It's really, really important for controlling inflammation in the brain, the structure of your brain. My very clever colleague, Kimberly Wilson, says that if you take out-- If you don't eat oily fish, it's a bit like taking out 25% of the bricks of your house and replacing them with polystyrene. 25% of your brain wants to be made from oily fish, right? So if you take it out of your diet, it's a bit like replacing 25% of the bricks in your house with polystyrene. It kinda looks the same structurally, but under a strong wind, [laughs] you're gonna have a real problem, and it's very much the same with our brain health. So you really wanna make sure you're getting at least two portions of oily fish a week or taking an omega-3 supplement. If you're a vegan, that could come from an algae oil source, and that's equally as good in terms of our brain function. But also, your gut bacteria love omega-3s, so it's really good for helping to promote the populations of, um, beneficial bacteria that helps control inflammation in the body, all that kind of stuff. So omega-3 from fish is super, super important for our bodies, but it's also a great source of lean protein.

    3. AAAli Abdaal39:15

       What do we mean by oily fish?

    4. SMSophie Medlin39:17

       So oily fish is, like, the ones that taste a bit more fishy, but salmon is a great example that people find really accessible, so that's good. But also mackerel is perfect. We could use sardines, that kind of stuff. The ones that are in tins, they're a bit more fishy. Those are the ones-

    5. AAAli Abdaal39:28

       Okay

    6. SMSophie Medlin39:28

       ... that people would benefit from the most.

    7. AAAli Abdaal39:29

       Tinned tuna?

    8. SMSophie Medlin39:30

       No. Unfortunately, not an oily fish.

    9. AAAli Abdaal39:32

       Oh.

    10. SMSophie Medlin39:33

        I know.

    11. AAAli Abdaal39:33

        That's annoying. [laughs]

    12. SMSophie Medlin39:33

        And that's the one we all eat, right?

    13. AAAli Abdaal39:34

        Yeah. [laughs] Okay, so salmon twice a week would be good for me.

    14. SMSophie Medlin39:38

        Perfect.

    15. AAAli Abdaal39:38

        Fantastic. I like salmon. Salmon is tasty.

    16. SMSophie Medlin39:40

        [laughs]

    17. AAAli Abdaal39:41

        Um,

13. 39:42 – 41:30

    How do supplements work?

    1. AAAli Abdaal39:42

       to what extent can I just be like, "You know what? I accept all this stuff, but I can't be asked to change my diet too much. If I just take the appropriate number of supplements, I'm good, right?"

    2. SMSophie Medlin39:53

       Yeah, no. No, it doesn't really work like that, unfortunately. [laughs] So we need to think of supplements as being, like, the icing on the cake, right? So we still need to do the foundational work if those-- if we want those supplements to be working for us. So it doesn't matter how many pills you pop. Ultimately, if your diet is terrible, you're really stressed all the time, you're not looking after your mental health, you're not exercising, you're not looking after your body, you're still gonna struggle. You're still gonna suffer. So you need to be doing some of those foundational things and then taking your supplements on top to try and get things in line. And with probiotics, that's even more important, because you can take as many probiotic bacteria as you like in capsule form, or as kefir, or however you want to, but if you're not feeding them with plant fiber when they get to your colon, they're not gonna survive. There's nothing there for them to eat. So we have to make sure that we feed them when they get there. Some people will put prebiotics, so food for good bacteria, in their supplements, but actually need quite a lot of that prebiotic fiber to make any difference. And actually, the best way of getting that prebiotic fiber is from your food, from the food that you're eating. So it's really important to encourage people to still maintain a healthy diet and look after all the other things, um, because we need to do all the things, unfortunately.

    3. AAAli Abdaal40:57

       Nice. Okay, so less than, well, 500 grams red meat per week, preferably two portions-

    4. SMSophie Medlin41:03

       Less than 500 grams, yeah. 350 to 500.

    5. AAAli Abdaal41:05

       Okay.

    6. SMSophie Medlin41:05

       You've got that down. [laughs]

    7. AAAli Abdaal41:06

       I've got it down. Yep. I'm like, "Damn." It's like a single steak is, like, about half that. [laughs]

    8. SMSophie Medlin41:11

       Yeah.

    9. AAAli Abdaal41:12

       Um, 30 grams of fiber a day, which most of us are not getting, so we need to add more seeds, grains, whole grains-

    10. SMSophie Medlin41:17

        Yep. Perfect

    11. AAAli Abdaal41:18

        ... fruit, veg, wood that has, like, texture and stuff to it-

    12. SMSophie Medlin41:21

        Mm-hmm

    13. AAAli Abdaal41:21

        ... 'cause that's fiber. Two portions of oily fish a week. Adding, adding in soya mince and tofu inst- to replace animal products-

    14. SMSophie Medlin41:28

        Yep, plant protein

    15. AAAli Abdaal41:28

        ... some of the time.

    16. SMSophie Medlin41:29

        Yep.

    17. AAAli Abdaal41:29

        Anything else?

14. 41:30 – 48:09

    Processed food, stress management and hydration

    1. AAAli Abdaal41:30

       What are some other hacks, I guess?

    2. SMSophie Medlin41:32

       Your gut bacteria does not like processed food, so we think that things like-- Well, if you imagine preservatives that are put in processed food are there to, to make sure bacteria doesn't grow, you can then extrapolate that and think, "Okay, well, what's that doing in my body?" So when I'm consuming these foods with preservatives, actually, are they- killing off my good bacteria or at least stopping them from growing. So that's something to think about. Emulsifiers that are in lots of processed foods and also in lots of foods that are, have got a bit of a health halo, like protein shakes and-

    3. AAAli Abdaal42:01

       Mm

    4. SMSophie Medlin42:01

       ... protein products, that kind of stuff. Emulsifiers, we think are disrupting the lining of people's bowels. So when we have too much of those kinds of things, the tight junctions between the cells in your bowel wall, we think are being disrupted and opening up a little bit, allowing too much inflammation into the body and causing all kinds of different problems, but also disrupting that really important mucosal layer in the bowel that is w- the home for our good bacteria. So emulsifiers, not great. Um, they're in plant milks and stuff like that, so we need to keep a little eye out for those. Um, anything that i- is kind of an added ingredient that you don't recognize is something that we want to be a little bit careful of, and there's this amazing data now about ultra-processed foods and how much they are impacting our risk of cancers and all kinds of other conditions. So an ultra-processed food is something that we do want to consider trying to avoid. Again, lots of pre- vegan products would end up in the ultra-processed food category, even though they've got this health halo. So we need to watch out for ultra-processed foods defined by all of these ingredients that you don't recognize. We want to think about, um, y- your gut bacteria just don't like them for lots of different reasons, but that's part of it. Processed meats in particular, gut bacteria really don't like those. When we're stressed, when we're really anxious all the time, we produce more stomach acid, we produce more enzymes, things happen differently in our gut. Lots of people will recognize that when they're stressed, they maybe have diarrhea or wind, or they're bloated, or they're uncomfortable, and so that's because when you're stressed, your structure and function of your gut changes slightly, and everything is more difficult. But also when it's a more acidic environment, that changes the pH of the gut. When the pH of the gut is changed, that has an impact on which bacteria can thrive and survive, and ultimately, if you've got too much stomach acid, and there's too, it's too much of an acidic environment, you're gonna develop more of the gut bacteria that are associated with more stress, more inflammation, worse health outcomes. So stress management, careful with ultra-processed food and processed food in general, and also drinking enough water. Gut bacteria really like to be very well-hydrated. So there's things that you can do as well as adding things in just to be a little bit wary of. But one of the nice things about gut health is really I'm talking to people adding things in. What more do you need to take in, as opposed to taking things away, which is kind of what ultra, like, diet culture is all about, right? So it's about, mostly about adding things in, and ultimately what we see from the data is when people add more plants in, it displaces some of these less healthy things in their diet anyway. So if you're snacking on nuts and fruit, you're not gonna be snacking so much on, on, you know, protein bars and stuff like that, so that helps people to move into these healthier patterns anyway.

    5. AAAli Abdaal44:24

       Love it. Um, does tea, coffee count as hydration, or does it have to be, like, water, water?

    6. SMSophie Medlin44:29

       So tea is quite good for hydration, and coffee and tea both contain something called polyphenols, which your gut bacteria love. Polyphenols are these kind of plant compounds that are in all different plants, and really importantly and interestingly, the different colored plants all have different polyphenols in. So, like, the purple ones are great for your brain health, and the orange and yellow ones are great for controlling inflammation and diabetes and stuff like that. So they all have slightly different jobs in our bodies, and tea and coffee contain important polyphenols that are really healthy and helpful for us. But coffee, you lose a bit of hydration every time you drink a coffee, so it kind of has a ne- negative effect in terms of your overall hydration, and that's because it's a diuretic, same as tea. So it makes you wee more, and you lose more water, and then you end up not as well hydrated. So what I recommend to all my patients is that while they're making a cup of tea or they're making a coffee, just drink a small glass of water on the side, and then you know that you've got enough going in, and also just trying to make sure people are drinking water through the day.

    7. AAAli Abdaal45:23

       Right, so the 300 mils of fluid in this, I'm net, like, less than that-

    8. SMSophie Medlin45:28

       Well, the-

    9. AAAli Abdaal45:29

       Because of the diuretic effect

    10. SMSophie Medlin45:29

        ... the data is not quite perfect, but I would say you're probably only getting maybe about 25 mils from that.

    11. AAAli Abdaal45:34

        Really?

    12. SMSophie Medlin45:34

        Something like that, yeah.

    13. AAAli Abdaal45:35

        Damn. Okay, I should drink more water.

    14. SMSophie Medlin45:37

        You should.

    15. AAAli Abdaal45:37

        Cool.

    16. SMSophie Medlin45:37

        We all should. [laughs]

    17. AAAli Abdaal45:39

        Um, what, how, how do I know if a food is processed? What are some rules of thumb?

    18. SMSophie Medlin45:44

        I mean, essentially, if it comes in a packet, if it's been through a factory-

    19. AAAli Abdaal45:48

        Yeah

    20. SMSophie Medlin45:48

        ... and it's come in a packet, it's gonna be processed to some degree.

    21. AAAli Abdaal45:50

        Like sausages.

    22. SMSophie Medlin45:51

        Sausages, um, any kind of, like, ready meal type stuff. There's lots of white bread that would fall, general breads that would fall into that ultra-processed category because to make bread you need, uh, flour, and you need yeast, and you need salt, and you need water. But the ingredients list on some of the breads that you might pick up on the supermarket shelf is gonna be so long and so complicated and have all kinds of preservatives and emulsifiers and stuff like that in it, that it actually ends up being an ultra-processed food. And we're in a difficult time, Ali, because people are struggling, right? It's a financial crisis. People are struggling to eat anything at all, so it's really important that we are careful about not demonizing food staples that people can afford. If you're living in a food ba- living off food from a food bank, and all you can get your hands on is baked beans and ultra-processed bread and cereal, you've got to eat it, right? I don't want anyone to take away from this that it's so harmful for their health they should go hungry. That's not the case at all. We're talking really here about refining health as opposed to people who are struggling, right? So there are ultra-processed foods that we need to be careful of, and we need to look at those labels. It's about those long ingredients lists with emulsifiers, things that have got a code, like colorings, E numbers, that kind of stuff. Those are the sorts of things to look out for, and that would be your, your clue that that's an ultra-processed food.

    23. AAAli Abdaal47:01

        Nice. So let's say you and I go to a local, I don't know, grilled chicken shop after this, and we get, and we're gonna get a takeaway. Or just in general, when at, when out at a restaurant, what are some good rules of thumbs for what people should order or should avoid ordering?

    24. SMSophie Medlin47:17

        I, like, I think if you're eating out, unless you're eating out every day or super, super regularly, you should enjoy it, right? It's an important thing to socially, be able to eat socially and to be relaxed when you're eating and not to worry about it too much. But the same kinds of rules would apply, so try to eat as many plants as you can, even if that means ordering an extra side of broccoli or spinach or whatever it is on the side of what you're having. We know that frying potatoes, for example, has an impact on our health in general, so fried potato products are not great for us, so try to limit those a little bit. I mean, chips are literally my favorite thing, so trying to limit those a little bit is helpful and important for people. So just sort of thinking, especially if you're eating out really regularly, where are my sources of vegetables here? Am I getting enough? Am I getting some lean protein? And trying to kind of piece things together in your mind about what's going on in, like on a, if you zoom out of your diet a little bit, what have I had to eat today? What do I need more of? What do I not need so much of, is helpful. But if you're eating out, you should enjoy it and have a nice time.

    25. AAAli Abdaal48:08

        Nice.

    26. SMSophie Medlin48:08

        [laughs]

    27. AAAli Abdaal48:08

        Um,

15. 48:09 – 51:39

    Does organic matter?49:14 Artificial sweeteners

    1. AAAli Abdaal48:09

       what's the deal with organic food?

    2. SMSophie Medlin48:12

       Yeah, I mean, nothing really. It's just really a marketing term. So there's no great data to suggest that eating an organic diet is going to have any significant health benefits for you. The pesticides and stuff that have-- are used in the food chain now are very carefully researched. There's very little data to show there's anything that might do you any harm. What is potentially more interesting in that field, which isn't really talked about, is that when soil has been really heavily, uh, commercially farmed, it becomes less rich in nutrients, then your fruit and vegetables can become less rich in nutrients. Whereas if we scale that down to kind of buying locally, so from your local farmers market, for example, less heavily, um, you know, farmed land, more nutrients in the soil, more nutrients in your fruits and vegetables. So buying-- And also food miles, so any food that's been through various different lorries and everything else, or airplanes to get to your plate, that's gonna have a depletion of those nutrients over time. So if you can buy local as much as you can, that's much more relevant really to our nutritional status than buying organic necessarily is.

    3. AAAli Abdaal49:11

       Oh, nice. Um, what's the deal with, uh, Diet Coke and other non-sugar-- z-zero sugar, but lots of artificial sweetener type drinks?

    4. SMSophie Medlin49:20

       Yeah, your gut bacteria don't like artificial sweeteners, unfortunately. Um, you know, they're, they're safe from like a cancer perspective and all that kind of stuff. There's not so much-- we don't worry too much about that kind of hype. But what we do know is that when we have artificial sweeteners, our body is anticipating having sugar, and things change to get ready to have that sugar. When it doesn't come, that has an impact. So there's data to suggest that it increases our insulin production, for example, which makes us ultimately, ultimately a bit hungrier and can have an impact on our general health as well. So ideally, sweeteners need to go in the no thank you bucket as well, which is difficult for people, right? Because, you know, when people are trying to get off sugar, sweeteners seem to be a good thing. And, and to be clear, if you're someone who is having loads of sugar right now, you're better off having some sweeteners and trying to wean yourself down a little bit rather than kind of trying to go cold turkey, which will ultimately probably fail.

    5. AAAli Abdaal50:07

       Mm.

    6. SMSophie Medlin50:07

       When I speak to people who have lots of Diet Coke in their diet or diet drinks in general, [laughs] I generally say, "All right, let's swap one. Let's do like an alternate thing." So if you're having four a day at the moment, let's go for like swap one for like a sparkling water, then have one next time, then have a sparkling water, then have another one, and just try to reduce it slightly rather than taking them away altogether.

    7. AAAli Abdaal50:26

       What's the deal with fruit juices?

    8. SMSophie Medlin50:28

       So fruit juice can have some benefits, right? It's got loads of vitamins and minerals in it and stuff like that, so some useful stuff. But also it's a-- still a, like a slightly processed food, and that means that our body handles it differently to how it would handle the whole fruit, for example. So if you eat-- you'd struggle to eat like five oranges, but you could have a glass of orange juice, even quite a small one, that's got the juice from five oranges in it. So it actually ends up being quite a lot of fructose, the fruit sugar there, and it's just a bit more difficult for our body to process it then, and we just end up having m- a bit more of a blood sugar spike and that kind of stuff that we don't really want to be encouraging. So a small glass of fruit juice every day is great. We're talking about something like 150 mils, but most people are chugging like a big bottle [laughs] of fruit juice, and that can end up being just, just more sugar than you want to be consuming in one go, basically.

    9. AAAli Abdaal51:10

       Um, is tomato juice special?

    10. SMSophie Medlin51:14

        So there's some interesting data around lycopene from tomatoes, which is a polyphenol, and, uh, its protection against things like prostate cancer, for example, in men. So there is some benefits to that kind of stuff. Lycopene's also really good for your eyes and other organs in your body. And of course, tomatoes have a lot less sugar in them than oranges or apples or whatever other sort of juice you might have. So again, a small jus-- glass of tomato juice would be good. You're still better off eating the tomatoes themselves 'cause you get all the fiber and all the other benefits then.

16. 51:39 – 1:04:39

    Nutrition and dieting myths

    1. AAAli Abdaal51:39

       I'm, I'm just gonna throw some bait at you because all-

    2. SMSophie Medlin51:41

       Sure. [laughs]

    3. AAAli Abdaal51:41

       All, all, all the health claims I've heard. Um, bananas are bad 'cause they don't have fiber.

    4. SMSophie Medlin51:45

       Bananas are great for you. This is-- I, I-- There was a medical conference a few years ago where, and it's famed now, where there's all this sort of really famed like low carb community there, and we can talk a bit more about low carb and why it's a bit dangerous, but like the low carber community have demonized bananas, and there was a medical conference with proper doctors, and everyone booed a banana when someone said, "And then I ate a banana, and this is what it did to my blood sugars." Everyone in the audience booed. They booed a banana. This is how [laughs] messed up this whole world has become. That is wild to me. A f- y- you know, let's say five years ago, I could at le- we could all just at least agree that everyone needs to eat more fruits and vegetables. And now the low carbers and the carnivores have come along, and even when I say, "You just need to eat more vegetables," but those people are like, "No, no, not true. You know, you shouldn't be eating this, you shouldn't be eating that." Nonsense. More plants, the better.

    5. AAAli Abdaal52:32

       Nice. The-- Okay, because I love bananas, and I've been being like, "Oh, banana bad 'cause carb and no fiber."

    6. SMSophie Medlin52:37

       No, no. You're all good.

    7. AAAli Abdaal52:38

       Um, low carb. What's going on there?

    8. SMSophie Medlin52:41

       Just starving off your colonic friends. I see lots and lots of patients in clinic who have had-- who've been on a ketogenic diet, in inverted commas, or been on a very low carbohydrate diet and ended up with really terrible IBS, ended up with horrendous piles 'cause they were so constipated, end up with all kinds of trouble. And the whole grains that we need to eat in or- in order for our gut bacteria to be as healthy as possible come from all sorts of different sources of whole grains. And so when we cut out carbs altogether, we're not having any grains whatsoever in our diet, and then we're starving off like really crucial species of probiotic bacteria that do these amazing things in our body that we talked about before. So when you go on a low carb diet, you're starving off some of your really important friends in your colon. You're not feeding them, and that leads to all kinds of trouble, including overpopulation of negative types of bacteria, which have negative consequences on our health. So eating a wide variety of foods, including grains and pulses and all that kind of stuff, is really, really important for our overall health and particular of our health.

    9. AAAli Abdaal53:37

       So if I'm trying to-- if I'm trying to get shredded and, [laughs] you know, keep the protein fairly high, reduce the calories, um, my tactic so far has been avoid anything that remotely looks like a carb unless a friend has got chips, 'cause it doesn't count if I steal a few, you know-

    10. SMSophie Medlin53:52

        [laughs]

    11. AAAli Abdaal53:53

        ... a f- a few of theirs. It sounds like you're suggesting the carbohydrates are evil approach is kind of bad, and instead I should be like, "Maybe I'll have- A little bit less rice than I normally would, but I've still got that in my system

    12. SMSophie Medlin54:04

        Yeah, totally, or have whole grain rice because you c- just can't physically eat as much of it. So whole grain carbohydrates keep us full for a long time, like protein does. So when we're trying to manage our weight, satiety, being full, is really, really important. So having higher protein diet, good. Having higher whole grain's really good for maintaining satiety, keeping you full between meals, stopping you snacking. And when people move to, like, having a small piece of fish and then loads of green veg, they're just starving all the time. Like, it's miserable, and it's not good for you ulti- ultimately. So let's try and balance that out a little bit. Get some whole grain carbohydrates in there. And I'm not talking about you going and eating a massive bowl of white rice or having, I don't know, a massive bowl of pasta. We're talking about having, introducing some more whole grain carbohydrates in your diet to feed your friends, keep you fuller for longer, and also try to manage your weight in the way that you want it to be managed

    13. AAAli Abdaal54:49

        All right, we're gonna take a very quick break from this episode to introduce our sponsor, which is Brilliant.org. I've been using Brilliant for the last several years, and they're a fantastic online platform for courses in maths and science and computer science. Brilliant is a fantastic resource for anyone who wants to develop new skills, but especially if you work or you want to work in a STEM-related field. It's an absolute no-brainer for being able to level up your knowledge of these topics. Brilliant has an enormous library of courses that cover all sorts of topics. And the courses are particularly good because they take a very first principles approach to the topic that they're trying to teach. Like, it's not just that they spoon-feed you information and expect you to memorize it, like often we were taught in school, but it's more like they teach you a principle, and then you apply it with some interactive puzzle or game or activity of some sort. And then they teach you a little bit more, and then you apply a little bit more. And it turns into this really interesting, kinda engaging teaching system, which is actually similar to the way that we were taught at Cambridge when I was in med school there, where you learn a little bit, and then you apply it, and then you learn a bit more. And you're generally paired with an expert in the field, and you kind of learn together and figure it out and build the building blocks of the knowledge in your own mind over time, rather than kind of being spoon-fed a fire hose of information and ex- expected to regurgitate it. One of my favorite courses on Brilliant, other than all the stuff on computer science, which is, like, my specialist subject outside of medicine, um, but they've got a really cool course on scientific thinking, and this course explores the laws of physics and engineering and just helps you generally get an understanding of how the world works. Brilliant are also constantly updating their lessons and courses. So for example, they've released a new course on crypto back when that was blowing up so people could understand that. They have a really interesting course on neural networks and how they work, which feeds into all the artificial intelligence stuff, and it's just a generally great way of keeping up with all these topics in the field of STEM. So if any of that sounds up your street, then do head over to Brilliant.org/DeepDive. And if you're one of the first 200 people to hit that link, which is also in the video description and in the show notes, then you'll get 20% off the annual premium subscription. So thank you so much, Brilliant, for sponsoring this episode, and let's get right back to the podcast. This episode is very kindly brought to you by WeWork. Now, this is particularly exciting for me because I have been a full-paying customer of WeWork for the last two years now. I discovered it during, you know, when the pandemic was in, on the verge of being lifted, and I'd spent, like, the whole year just sort of sitting in my room making YouTube videos. But then I discovered WeWork, and I was a member, me and Angus, my team members, we were members of the WeWork in Cambridge, and they have, like, hundreds of other locations worldwide as well. And it was incredible because we had this fantastic, beautifully designed office space to go to to work. And we found ourselves, like, every day, just at 9:00 in the morning, just going to WeWork because it was a way nicer experience working from the co-working space than it was just sitting at home working. These days, what me and everyone on my team has is the All Access Pass, which means you're not tied to a specific WeWork location, but it means you can use any of their several hundred co-working spaces around London, around the UK, and also around the world. And one of the things I really love about the co-working setup is that it's fantastic as a bit of a change of scenery. So these days I work from home. I've got the studio at home. But if I need to get some focused writing work done and I've been, I'm feeling a bit drained just sitting at my desk all day, I will just pop over to the local WeWork, which is about a 10-minute walk from where I am. I'll take my laptop with me. I'll get some free coffee from there. I'll get a few snacks, and it's just such a great vibe, and you get to meet cool people. I've made a few friends through meeting them at WeWork, and it's just really nice being in an environment almost like a library, but kind of nicer because there's, like, a little bit of soft music in the background, and there's other kinda startup bros and creators and stuff in, in there as well. And it's just my absolute favorite co-working space of all time. It's super easy to book a desk or book a conference room using the app, and it's a great place to meet up with team members if you're gonna collaborate and you all live in different places. They've got unlimited tea and coffee and herbal teas and drinks on tap, and they've got soundproof booths in which to take Zoom calls and meetings. Anyway, if you're looking for a co-working space for you or your team, then I'd 100% recommend WeWork. Like I said, I've been a paying customer for theirs for the last two years, which is why it's particularly exciting that they're now sponsoring this episode. And if you wanna get 50% off your first booking, then do head over to we.co/Ali, and you can use the coupon code ALI at checkout, A-L-I, to get 50% off your first booking. So thank you so much, WeWork, for sponsoring this episode. What's the deal with a ketogenic diet?

    14. SMSophie Medlin58:30

        I mean-

    15. AAAli Abdaal58:30

        Loads of tech bros are particularly-

    16. SMSophie Medlin58:32

        I know

    17. AAAli Abdaal58:32

        ... like, big on that.

    18. SMSophie Medlin58:33

        I know. I wish they would stop. [laughs]

    19. AAAli Abdaal58:35

        [laughs]

    20. SMSophie Medlin58:35

        So the ketogenic diet was developed for children with epilepsy, which I think is a fairly commonly known story now. The only indication for a ketogenic diet is for children and adults who have epilepsy-

    21. AAAli Abdaal58:44

        Really?

    22. SMSophie Medlin58:44

        ... because, yeah, totally.

    23. AAAli Abdaal58:45

        Oh, wow. [laughs]

    24. SMSophie Medlin58:46

        Yeah, yeah. So we use it in clinical practice for that sole purpose, nothing else. And there is some really interesting data and useful data now that suggests that lower carbohydrate diets are helpful for weight control. But there are inevitably consequences to that in terms of microbiome and other things. So lower carbohydrate diet's useful and generally reasonably sustainable for people who need to lose a lot of weight over a long period of time. But ketogenic diets, where the carbohydrate intake is so low, are, like, almost consistently completely unsustainable for people, meaning that they then fail on potentially another diet. They feel like they're a failure. Nothing can happen. They can't do anything. Their kind of self-esteem, their self-ef- efficacy goes right down. People give up on weight loss, and everything gets to be a disaster. So it's all about balance and managing things properly, and no qualified dietician or other healthcare professional would recommend a ketogenic diet to anyone because we are aware of the consequences. It's just the, I don't know, shouty people that are not properly qualified in this area that are doing it.

    25. AAAli Abdaal59:47

        What are your thoughts on one meal a day?

    26. SMSophie Medlin59:49

        I mean, can you get 30 plants in one meal a day, Ali?

    27. AAAli Abdaal59:52

        Probably not. [laughs]

    28. SMSophie Medlin59:53

        Yeah, exactly. That's my thoughts on it. Essentially, that's a summary of my thoughts on it. You cannot possibly get all of the nutrients that you need for one day in one meal because you can't physically fit it into your body. And so ultimately, you're gonna be Affecting your gut health, affecting your general health. And, you know, if you think about the opportunities that you've got to have oily fish twice a week, for example, you're gonna have to think about that over one meal rather than having more than one opportunity to have those really healthy things. So if you think you can fit at least five portions of fruits and vegetables, and nuts and seeds, and all the other stuff that you need to have to be healthy into one meal a day, hats off to you, but I don't think you'll be able to fit it in your body. [laughs]

    29. AAAli Abdaal1:00:31

        Nice. Um, what's the deal with the carnivore diet?

    30. SMSophie Medlin1:00:35

        Oh my God. The carnivore diet is just, I think, one of the worst things that's happened recently, isn't it? I sh- it's, it's horrendous for your gut health, right? Horrendous. You're obviously completely starving off your microbiome. These guys are inevitably going to end up with, and, it is mostly guys, are [laughs] going to end up with heart disease, with high cholesterol, with all kinds of problems, but their colons are gonna be in absolute mess because they're basically only feeding those negative bacteria that are having health, negative health consequences 'cause their diet is just protein. So for anyone that doesn't know, and please don't Google it, the carnivore diet is where you just eat meat. And there was this guy, I can't even remember what he called himself now, but he was like the king of the carnivores, right? The Liver King.
17. 1:04:39 – 1:14:43

    How has diet culture evolved?

    1. SMSophie Medlin1:04:39

       but it was very much the thin ideal. So the thinner the better at all costs. There's no such thing as too thin. Kate Moss generation of, like, then sort of a bit later, Kate Moss generation of nothing tastes as good as skinny feels. These were all the messages. Funnily enough, I was having a conversation with my friend this morning about the sidebar of shame, which was basically pictures of-- This is in more in the '90s of, like, Jennifer Lopez with a tiny bit of cellulite on the beach circled saying, "Sidebar of shame," in the Daily Mail. In women's magazines, it was all about the thinner the better, and anyone seen to be carrying any additional weight was shamed, circle around the bit that they were saying was not good, all that kind of stuff. And then, of course, when women did lose too much weight, they were told they were too skinny, and everything was awful, and they had something wrong with them, but they've just been shamed into it. And then we had the social media, and we had Instagram. And so if we think about Instagram coming in something like 11 years ago, now young women are exposed to all sorts of different shapes and sizes of bodies now, but the, the body shape that we're told that we have to have now is this kind of tiny waist, massive bum, big boobs, but you have to have a thigh gap, and you have to be able to fit your fingers around, hands around your waist. [laughs]

    2. AAAli Abdaal1:05:44

       [laughs]

    3. SMSophie Medlin1:05:44

       And, and you have to do this, and you have to have visible abs and everything else. And a lot of that stuff is obviously, not necessarily obviously, it's physiologically impossible unless you've had surgery, right? So if you're doing loads of squats, unless you have a very specific pelvic shape, if you're doing loads and loads of squats, you're gonna build up your inner thigh muscles as well. So you end up without a thigh gap, but you might have a big bum, but you've not got a thigh gap that you wanted. So you keep working, you keep trying, you think, "I'm not losing enough weight. I'm not doing it right." But actually, those people that you're looking at are either posing in a very unnatural way, or they've had surgery, or they're editing their pictures. So we're now exposed to this kind of-- And, and, you know, even, like, the Kardashians lead a lot of this body, uh, body image Stuff, in my opinion, and in everyone else's opinion. [laughs] Now, now they're going very skinny, and that's really hard because peop- women have maybe eaten a bit extra to try and bulk up, and maybe they've had this surgery to make their bum bigger, and now the Kardashians are getting really skinny, and they're like, "Oh, my God, what am I gonna do? Have my bum implants taken out? How am I supposed to manage this?" Right? So social media has caused this absolute chaos with body image and with diet culture, and just, like, some interesting examples of this. Like, nobody in the world told, like, from a nutrition professional perspective, told people to start drinking plant milk. That was almost entirely led by, like, a social media campaign of people saying you shouldn't be drinking dairy, and then plant milk has come along and taken up that space. Nobody in a nutrition professional perspective has said that's better for you in any capacity than drinking dairy milk, because it's not. Fundamentally, dairy's got loads of really important nutrients in that are harder to find elsewhere in your diet. But somebody came along, and I could name her, but you might wanna edit it out. Deliciously Ella came along and said-

    4. AAAli Abdaal1:07:21

       Oh, interesting

    5. SMSophie Medlin1:07:21

       ... everyone should be plant-based and not drink dairy, and now there's this huge market for plant-based milks, right? At that time, so we're talking almost kind of 11 year ago, uh, no nutrition qualifications, by the way. 11 years ago, along comes Joe Wicks and tells everyone to eat coconut oil. Coconut oil's full of saturated fat, and we worked so hard as nutrition professionals to get people away from saturated fat and to have more olive oil, and now suddenly everyone's eating loads of coconut oil because Joe Wicks told them to. Again, no nutrition qualifications. Absolutely no health benefits to eating coconut oil. But these nutrition trends seep into society, uh, from influencers and from social media platforms, and it, it causes physical harm. So if we get a wave, and you know, lots of people would say it's inevitable that we have a wave of young women and men who have osteoporosis in their 40s because they never gained the bone density that you get from having dairy in your diet consistently up until the age of 30, is Deliciously Ellia-- [laughs] is Deliciously Ella or other influencers culpable for that? Are they responsible? I think so, but no one's gonna-- They're not, they've not got any governing body that says that they should be.

    6. AAAli Abdaal1:08:23

       Mm.

    7. SMSophie Medlin1:08:23

       Equally, if we did have a big spike in heart attacks from people having loads of coconut oil, is Joe Wicks responsible? Maybe, but he's not culpable because he's not, he's not got any credentials in the area. There's no one governing what he's saying. There's like, social media has become a public health platform, but nobody is managing it, nobody's protecting it, no one's making sure it's okay. Skinny teas giving people diarrhea, teaching people purging behaviors. Like, it's a mess, [laughs] and it's so hard to break through that stuff, and I think dieticians have such an important voice there, but it is really hard to break through, and that is where now diet culture is, like, on acid, and it's so dangerous for people.

    8. AAAli Abdaal1:09:00

       Damn. [laughs]

    9. SMSophie Medlin1:09:01

       [laughs]

    10. AAAli Abdaal1:09:02

        I did-- I've done two DEXA scans in the last, uh, sort of 12 months. First was in June, then was in December, and the one in June showed me that I was, like, 24% body fat or something, which was a real shock to my system because I just kind of assumed I was, like, 17, 18% or something just based on how I think I look. Um, and the guy who did the scan, uh, was like, "Yeah, you know, m- in terms of, in terms of your upper body, you're sort of median for people who, the sorts of people that have DEXA scans, i.e., generally more health-conscious-y type people. For your lower body, you're in the 15th percentile, so do more squats," kind of thing. Um, but also I had tons of visceral adipose tissue. It was like 17 something. And then I had another scan six months later. Uh, I'd lost three kg. Annoyingly, like, 60% of it was muscle rather than fat. Um, and the guy was like, "Yeah, it's 'cause not enough protein and not enough actually going to the gym," which is what maintains muscle when you, when you've lost weight. The visceral adipose tissue went down to sort of the 50s from the 70s, which was good. Um, body fat was still, like, 23%. Um, and so I was thinking-- part of me was thinking, "I wanna get shredded," um, just for the aesthetic stuff. But then another part of me, well, when I s- when I spoke to this other health coach, he was like, "Well, it's not, it's not really about the six-pack abs, but actually we do wanna get this visceral adipose tissue down." And especially with my background, South Asian, basically, apparently a lot of fat congregates around our bellies. Um, and visceral adipose tissue equals bad, therefore I should try and reduce my overall body fat because that gets rid of some of the visceral adipose tissue. To what extent, uh, is this reasonable strategy or w- what have I gotten wrong in this analysis? Yeah.

    11. SMSophie Medlin1:10:34

        No, no, I mean, all of what you've said is true. So v- visceral fat, which is the fat that collects around your organs, is really not good for our general health. It's very metabolically active and interacting with our body. It creates inflammation in the body, which we know to be really negative for us. So visceral fat is something we need to control. How much visceral fat you have is inevitably going to be linked to your genetics. So you will always have more than perhaps-- So when we do these studies, the DEXA studies to show what's average are mainly done on white people, and so we don't necessarily have a good gauge of what might-- that might look like in South Asian people, for example, what might be normal. So actually, if you did compare that, and BMI is the same actually, so we give a lower BMI and waist-to-hip ratio for South Asian people now than we would for white people because South Asian people, uh, carry more weight centrally, and that's-- so you might be lighter, but you might carry more weight centrally, and that's more dangerous. So actually, if we looked at studies that include people from all different backgrounds, there might be a slightly different ratio for you of what would be normal, right? Because of your background. So that's something to think about. I don't believe that data exists, but I could be wrong. Um, so it's something to do with thinking practically about what's right for you and whether you can physically do that. But focusing on something like visceral fat is a useful measure of thinking, "Okay, how am I gonna improve and, and, um, impact my long-term health?" Unfortunately, most people are only interested in aesthetics to the detriment of all the other things, and then that can end up with all kinds of different problems. So you could get really, really fixated on that number, and actually it's not moving as fast as you want it to, and that can be really difficult for you because you end up in a bit of a pit of going to the gym twice a day and hardly eating anything or just eating protein and go down this spiral. Whereas actually just having a, a gauge on it, having an eye on it, and making sure it's not becoming out of control and in a really unhealthy level is probably the most important thing to think about.

    12. AAAli Abdaal1:12:15

        How do you feel about the visible abs culture? [laughs]

    13. SMSophie Medlin1:12:18

        [laughs] I mean, I think it's-- unfortunately, I think it's much more dangerous for women than it is for men, so... That's not fair. I think that- There's this culture now for men, and I really feel sad that women haven't brought men with them on the posit- body positivity journey, 'cause I think that the d- like diet culture journey is really just in its infancy for men really. But what I notice is if you watch Netflix, for example, you'll see men who don't apparently go-- You might follow this man all through his day and he's doing all sorts of different things, but not once has he gone to the gym. But when he takes his shirt off in the evening, he's got this absolutely ripped six-pack.

    14. AAAli Abdaal1:12:50

        [laughs]

    15. SMSophie Medlin1:12:51

        So young men are like, "Oh, he's not really going to the gym, but h- somehow he look..." Like, every man has this under their-- Like, even lawyers who are clearly working like 24 hours a day seem to have this amazing six-pack. How is that possible? How do I get that? I should have that too.

    16. AAAli Abdaal1:13:04

        Mm.

    17. SMSophie Medlin1:13:04

        And of course, that's not how it is, right? [laughs] That's just not what the average man looks like, but that's what men are now expected to kind of try and emulate or feel that they're expected to try and emulate. And, you know, the lower your body fat percentage goes, the lower your testosterone gets, the more higher risk you are of injury, and generally your energy is gonna be crap. If you speak to people who are men who've been on the front covers of like, uh, Men's Health and stuff like that, and you ask them how they were feeling at the time that they shredded down for that photo shoot, they'll tell you that they felt horrendous, that they were depressed, they felt awful. They hadn't eaten out, and they just hadn't eaten with their wife for ages, they hadn't seen their kids for ages 'cause they're just in the gym all the time. You know, that-- And they've not drunk enough water. They've, like, fasted from water to try and get really shredded. But that's kind of the, you know, the panacea. That's what people are aiming for, right? That's what people think they need to be looking like. So that's dangerous and toxic in and of itself. When we think of women, actually having visible abs for most women means getting your body fat percentage down to something that we're relatively similar to men, so something below, like, 19%, let's say. But in order for a woman, most women, this is on average, looking at data, most women need a body fat percentage of at least 22 to 25 to have a regular menstrual cycle. So women are starving themselves down to body fat percentage of somewhere between 17 and 19 to get visible abs, meaning that their menstrual cycle has probably stopped on average, if we look at it. And of course, some women carry a lot more weight on the bottom and not so much in the middle, so they might have leaner abdomens naturally. But on average, when we look at the data, most women with a six-pack probably won't be menstruating. And of course, not having a period is associated with all kinds of really negative health outcomes, not least of all, uh, you know, bone density problems and all sorts of things that are actually long-term health things that can cause all kinds of harm.

    18. AAAli Abdaal1:14:42

        One

18. 1:14:43 – 1:21:57

    TOFI vs TOFI people

    1. AAAli Abdaal1:14:43

       of the questions that people love to ask, I think, in m- media type stuff I've seen, and so I'm, I'm gonna ask it to you with that caveat, with the, with, with the apology, but, uh, is can you be overweight and healthy?

    2. SMSophie Medlin1:14:53

       Yeah, for sure. Yeah, yeah. So some people just are naturally supposed to be heavier than what the BMI tells us to be. And in my practice, I would say that those are the people who were-- noticed that they were heavier as children, and maybe they carry a bit more weight on their lower body or on their arms. Maybe they're women who've got quite big breasts, that kind of stuff. They generally just are naturally heavier. Maybe their mom's also a bit heavier and, or their grandma and their grandma was a bit heavier. That kind of genetic predisposition to carrying a bit more weight. But what I'm talking about is women who eat really well, who look after their bodies, who exercise, who love exercise, who are doing really good stuff, and who look after their mental health and are not eating compulsively. They don't feel out of control with their relationship with food. They're eating really healthily, but ultimately, they are still heavier than what their doctor might like them to be, right? And those are healthy people. Those are overweight but healthy people. And what we have is this interesting data around people who are thin on the inside but fat on the outside, TOFI, and FOTI people who are fat on the outside but thin on the inside.

    3. AAAli Abdaal1:15:48

       What does that mean?

    4. SMSophie Medlin1:15:49

       So [laughs] thin-- You could be thin on the outside but fat on the inside, like with this visceral fat we're talking about.

    5. AAAli Abdaal1:15:53

       Yeah.

    6. SMSophie Medlin1:15:54

       So you could be a naturally very thin person, but maybe you're smoking, maybe you're drinking too much, maybe you, you know, don't eat well, you don't look after-- like you never exercise. So you might look thin, so your doctor goes, "Sure, you can have IVF, you can have all this treatment, you can do these things," but you're actually r- a very, very unhealthy person and just some small lifestyle changes might sort everything out for you. But you could be an overweight person, overweight in inverted commas, who looks after their body, everything beautifully, doesn't have hardly any visceral fat, but they are naturally a heavier set person, and they're denied treatment for things like infertility and that kind of stuff because their BMI isn't what their GP wants it to be. So it's a big kettle of fish, and it's very difficult, but yes, you can absolutely be heavier than the society would like you to be and be a very healthy person.

    7. AAAli Abdaal1:16:36

       I've, I've heard on a, a couple of usually, um, kind of men-centric podcasts, um, this idea of, and usually right-wingy type podcasts, that, "Oh my god, woke culture has gone mad. You look at that plus-sized model on that-

    8. SMSophie Medlin1:16:52

       Yeah

    9. AAAli Abdaal1:16:52

       ... on that Instagram page. Look at that plus-sized model on that magazine cover. Yes, we get that, like, body shaming, bad. Yes, we get that, like, super, super skinny, also bad. But like, come on, sh- surely you're encouraging women to become fat." That, that-

    10. SMSophie Medlin1:17:04

        Sure

    11. AAAli Abdaal1:17:05

        ... that kind of narrative. What, what, what do you think to that?

    12. SMSophie Medlin1:17:06

        Yeah. I mean, the-- when we think about, um, my, my mom's generation again, where they only saw very, very skinny women, and certainly to the early stages of social media, where we only saw a very particular shape and size of women, and we still see that on TV on average and everything else, when we see that and we don't see any other body shapes and sizes represented, it means that the women who can never be that shape and size, despite however much exercise and, and healthy eating, whatever else they do, they just feel completely unrepresented. And those people who, you know, you might follow the latest diet trends, every new one that comes out, but it's not working for you because you're just never supposed to be that shape and size. It's not healthy for you. It's impossible for you to maintain, get there or maintain it. So you either develop an eating disorder or you develop what we call disordered eating, where you're feeling terrible about your body shape and size all the time. You're bouncing from, you know, either completely restricting or overeating all the time and struggling to maintain your, a healthy relationship with food. You're constantly thinking about food. It's the only thing you're ever thinking about. You're hating your body and thinking about food all the time. It's occupying all of your brain space. Imagine what you could do with all that brain space if it stopped. Um, when we don't have any representation, that's the two camps that people fall into. So they either stay super, super skinny, or they really struggle with disordered eating relationship with food and their body. What we need is this representation. And of course, we don't need any glorification of poor health. But what I see from these girls that are, you know, these plus-size models who are on the cover of Cosmopolitan, if you look on their Instagram, they're skipping, they're doing yoga, they're doing amazing things. They're doing incredible stuff. They're not-- Generally, the, the people who are shown are not the people who are on YouTube Eating excessively and everything else, right? Those are, that's a really niche kind of fetishy category actually. [laughs] But I think that these heavier women who are naturally heavier and are plus-size models are being grouped in with them, and that's certainly not how it is in reality.

    13. AAAli Abdaal1:18:53

        All right, so we took a little bit of a, a tea break. I did the thing that you, that, that you suggested. While I, while, while I was waiting for the tea to steep or brew or whatever the hell that's called, I poured myself a glass of water and I drank it.

    14. SMSophie Medlin1:19:03

        Perfect.

    15. AAAli Abdaal1:19:03

        And that's such an easy thing.

    16. SMSophie Medlin1:19:04

        Yeah.

    17. AAAli Abdaal1:19:04

        It's so nice when you can, like, attach a habit to something else.

    18. SMSophie Medlin1:19:07

        Definitely.

    19. AAAli Abdaal1:19:07

        So that's good. Yeah.

    20. SMSophie Medlin1:19:08

        I think that's where dieticians come in really handy, 'cause we understand, like, if you see a different sort of nutrition professional, sometimes you're given this, like, idealized diet of the perfect things you should be eating and drinking, and it's just completely unrealistic, whereas because we work in hospitals with people who just don't have access to funds and stuff like that for the majority of our career, you kind of understand what people actually like and how they really behave, and then you can really help people to kind of change those behaviors rather than just going, "Here's your diet plan. Off you go."

    21. AAAli Abdaal1:19:32

        Yeah. Um, uh, on, on that note, are there any other sort of quick, easy tips that someone can, can take away that will just level up their life? [laughs]

    22. SMSophie Medlin1:19:40

        I think, like, snacking on nuts and seeds and stuff like that is just so helpful.

    23. AAAli Abdaal1:19:43

        Okay.

    24. SMSophie Medlin1:19:43

        Just add in, add things in. Put like a jar, like a ... If you're someone who eats in the car and you notice you on eat unhealthy things in the car, put like a jar of trail mix in the car.

    25. AAAli Abdaal1:19:52

        Okay.

    26. SMSophie Medlin1:19:52

        Go to a health food store or wherever you can afford to. You can go to, um, Poundland and get loads of different nuts and seeds and stuff, and mix them up in a big jar and put that in your car, and it will help you to kind of keep full for ages and have nice things to snack on.

    27. AAAli Abdaal1:20:03

        Interesting. So I've always thought, like, I really like nuts, but then I think, "Oh, nuts, high-calorie, bad." [laughs]

    28. SMSophie Medlin1:20:08

        So interestingly, there's great data to show that the less you chew nuts, the less nutrition, like, the less fat you absorb from them. So don't choke, but [laughs] if you-

    29. AAAli Abdaal1:20:18

        Just swallow them. [laughs]

    30. SMSophie Medlin1:20:18

        Yeah, swallow them whole. Um, you just can't act- They're very difficult to digest in a really positive way. So ultimately, the, if you eat nuts, you just don't, you probably absorb 50% of the fat from the nuts that you actually eat, because most of us aren't chewing it down. If you have peanut butter, for example, then you end up absorbing much more of the fat, because obviously it's processed and you can eat it better.
19. 1:21:57 – 1:24:41

    Research on probiotics and mental health

    1. AAAli Abdaal1:21:57

       [laughs]

    2. SMSophie Medlin1:21:57

       Yeah, so there's some great research on probiotics and both the gut-brain axis, so how when we're stressed, we have these gut symptoms, and how probiotics can help to control those gut symptoms. So one in particular, so there's 55 healthy volunteers given a probiotic. Another group are given, uh, a placebo, so we can measure the difference. The ones who have the probiotic have a significant reduction of psychological stress, significant reduction in cortisol, so these, like, chemical parameters of stress and anxiety that we can measure. So it's not just how people say they're feeling, it's these objective measures. So when we're talking about Serobiome, which is these two, combination of two particular probiotic bacteria, which we have in the smart probiotic, shown to significantly reduce cortisol in people who are taking it in comparison to placebo. Magic. People don't believe this stuff until they see some of this research, right? It's so important to look at it. And they also see d- d- a decrease in depression scores, so people's perceived how they're feeling, mood scores, that kind of stuff, which is pretty magic. I think one of the really important things that we often miss when we're thinking about productivity and focus and concentration is that anxiety is, like, the anti-focus concentration hormone, right? When you're anxious, you generally procrastinate. You don't wanna do anything. You get really fidgety, so you can't concentrate on anything at all. So really, w- with a lens of thinking about why we struggle with focus and concentration, we've gotta think about anxiety. So if we can reduce anxiety and reduce cortisol, we're gonna be in a much better flow state.

    3. AAAli Abdaal1:23:18

       Yeah.

    4. SMSophie Medlin1:23:18

       We're gonna be able to focus much better. So if we're focusing our, our thoughts about this on reducing of co- cortisol, we can think that then the counteraction of that will be that you'll be able to concentrate and focus much better. We've also done some great re- There's great d- research on depressed patients given probiotics and seeing improvement in anxiety, sleep quality, stress. And that, in that study in particular, they were given the probiotic for eight weeks, and those results lasted for eight weeks longer once they stopped taking the probiotic, which is pretty magic. So your gut bacteria adapt and change over time, and then they can become a less stressed microbiome. So your, y- ecosystem in your colon sort of evolves with you. So it evolves depending on what you feed it, and it evolves depending on what external factor's going on. So if there is a lot of stress, you become a more stressed ecosystem, into, including your colon, and that then helps to release more cortisol, makes you a more stressed person. So it's this feedback loop between your gut and your environment, whereas if we can break that feedback loop by introducing some probiotic bacteria that help to control stress, it can help to have long-lasting effects on your colon, which is magic. And then we've got another great study with 75 healthy volunteers given placebo or probiotics, and again, really significant reduction in stress-induced GI symptoms. So that diarrhea that you get when you're feeling anxious and stressed, we can see that reduced just with taking these two particular strains of probiotics, which is pretty magic.

    5. AAAli Abdaal1:24:36

       That's really cool. Sick. [laughs] I'm gonna take this more, more regularly now.

20. 1:24:41 – 1:26:15

    IBS

    1. SMSophie Medlin1:24:41

       Yeah, every day, please.

    2. AAAli Abdaal1:24:41

       Although we can cut that out because-

    3. SMSophie Medlin1:24:42

       [laughs]

    4. AAAli Abdaal1:24:44

       One thing that is common for people to hear if they go to a doctor about some, any kind of bowel symptoms is, "Oh, you've got a bit of IBS."

    5. SMSophie Medlin1:24:52

       Yeah, sure.

    6. AAAli Abdaal1:24:53

       What does a bit of IBS mean? [laughs]

    7. SMSophie Medlin1:24:54

       Nothing, really. [laughs] I think it's really important that everyone knows that if a doctor is trying to give you a diagnosis of IBS, diagnosis o- of IBS is a diagnosis of elimination. So your job as a doctor is to eliminate all the other things that it could be before you say it's IBS. So that means that at the very least, someone should be having a blood test to rule out any sort of inflammatory condition, and they should be having a stool test, again, to look at inflammation in the stool, but also to look for any blood in the stool, which is associated with bowel cancers. And unfortunately, bowel cancer is affecting more and more young people. We also, with women, we would think about things like endometriosis and other gynecological problems that could cause disruption to digestion, but also bloating and that kind of stuff. Uh, you know, cervical cancers can lead to bloating, those sorts of things. So it's so, so important that your doctor does that process of elimination before they give you that diagnosis of IBS. And I think it can be quite empowering for people to know that actually the NICE guidelines, so that the guidelines that tell doctors what to do, that it's in there. They have to do this process of elimination before they say it's just a bit of IBS, because there is a risk that you'll miss other, much more serious things. And a lot of my patients will have seen their doctor multiple times before they see me, and then they come, and they say, "My doctor said I've got IBS." And then I say, "Actually, I just think we need to do a few more tests. I don't think this has been ruled out." And they end up having something more serious, and that's, you know, it co- could've been diagnosed years ago.

    8. AAAli Abdaal1:26:14

       Hmm.

21. 1:26:15 – 1:32:36

    What can we learn about the gut through testing?

    1. AAAli Abdaal1:26:15

       What can we learn about gut from poo testing and blood testing?

    2. SMSophie Medlin1:26:19

       So stool testing at your GP-- So if someone comes to see me, and I think, "I think we need some more stool tests," the sorts of stool tests I might ask for would be things like, um, a s- it's called a fecal calprotectin, so it measures how much inflammation is in your poo, and that tells us if there's actual inflammation in your bowel. Someone who has IBS should never have inflammation in their bowel. It's just not part of the IBS picture. But people who have inflammatory bowel disease, for example, may well have infla- well, will have inflammation in their bowel itself when they're in, have active disease. Um, we can also look for things like parasites. So sometimes people come, and they've got, like, IBS that developed when they went on holiday somewhere, and actually they've got some residual giardia or another parasite that they've picked up, that kind of thing. We can also look for things like H. pylori, which is a particular type of bug that lives in your stomach lining, and that can cause reflux and those kinds of things, and it's, again, a simple stool test that can be done for that. So there are lots of medical level stool tests we can do. We can check your pancreatic function with your stool test, that kind of thing. But the sort of stool tests that people are really interested in now are these microbiome tests that you can have done. So these are available commercially, and they are interesting. So [laughs] in the last week, I've been analyzing a load of stool tests as part of the Heights probiotic trial, and we're looking at people's stool tests. But there's real limitations to them. So we've got really interesting raw data, and what we need to do with that data is pair it up with what people are eating, what their lifestyle's like, try to use the clues from their clinical conversation with them to then look at their stool tests and try and match up why this particular thing is different for them. So for example, you could look, and you could say, "Oh, this person's got more higher levels of some pathogenic bacteria," and you need to say, "Did you have food poisoning any time in the last kind of few years or so?" And then we can go, "Okay, that's probably why." But it might also just be a bit high 'cause their levels of good bacteria are a bit too low, and we need to balance it all out, so it's all about ratios. And I guess the main thing to take from this is that if you're gonna do it on your own, the chances are you're gonna end up with a load of information that you don't know what to do with, [laughs] and it can be potentially really frightening. And if you have existing gastrointestinal problems, the more anxious and, and worried you are, the worse your problems are gonna be, right? [laughs] So it's not necessarily helpful to do it if you are someone who is feeling anxious, and you think that might be contributing to your gut symptoms. Ultimately, there's really no point in doing it if you're someone who lives with any kind of gut condition because we just don't have data for what is normal for someone who has IBS, for example. So we've got loads of data for what's normal in healthy people or what's average in healthy people, but we don't have data on people who've got IBS, IBD, that kind of stuff. So it's just not a good idea to do it if you've got any kind of gut symptoms. And actually, if you come and see someone like myself or someone from my team, we can, based on your symptoms and what's going on for you, have a really good guess at what's going on bacteria-wise, right? So if you say to me, "I'm passing really foul-smelling gas," I'll say, "What does it smell like?" And they might say, "It smells really eggy." And I'll say, "Yeah, you've got too many of the ones that produce too much sulfur. Let's work on managing those." And if you say, "I've got really bad bloating," I'll say, "Well, you've probably just got really loads of rapid fermenting bacteria in there, and we can try and modulate the proportions of those so that things get a bit more comfortable." So it's, you really don't need to have one ever, but sort of academically speaking, they're always quite fascinating.

    3. AAAli Abdaal1:29:17

       Hmm. So I was in Miami a couple of days ago, and everyone there seemed to have some kind of longevity regimen-

    4. SMSophie Medlin1:29:24

       Sure

    5. AAAli Abdaal1:29:24

       ... with their NADs and NMNs and all their stacks and all this kind of stuff. And one thing that they all, well, sauna use, cold showers, ice plungers, hyperbaric chambers, even some of them, one thing that they all seemed to have done was some kind-- I think this sort of microbiome stool test thing.

    6. SMSophie Medlin1:29:37

       Yeah. Mm-hmm.

    7. AAAli Abdaal1:29:37

       'Cause they were like, "Oh, I did my stool test, and it told me that actually for me, avocados are really bad, and for my mate, avocados are good." Like, what?

    8. SMSophie Medlin1:29:45

       Sure.

    9. AAAli Abdaal1:29:45

       I, and I was a bit like, "What? How, how does that work? What's, what's going on there?"

    10. SMSophie Medlin1:29:49

        I think that what they are referring to is, um, some personalized nutrition program that does stool testing, but also does blood testing and genetic testing.

    11. AAAli Abdaal1:29:57

        Yeah. Yeah, they do. The whole shebang. Yeah.

    12. SMSophie Medlin1:29:57

        So they're looking at the full parameters of things. And whilst that's interesting, ultimately the, the vast majority of the vi- advice, both on microbiome testing, but also on genetic testing and everything else, is gonna be roughly the same, right? Roughly the same, which means that you, you've got a slightly higher propensity to me for cardiovascular disease, for example, and I have a slightly higher propensity for diabetes. But the dietary advice for those two things is gonna be the same. [laughs] Eat loads of plants, have some oily fish, be careful with high-fat foods, that kind of stuff, yeah? So the dietary advice is gonna be roughly the same regardless of what's going on. And some people might find out from that kind of stuff that they don't handle fats very well. So they might find out that actually for them, avocado, too much avocado isn't a good thing. But most people aren't out there smashing so much avocado that it's gonna have a negative impact on their health, right? So ultimately, those tests are interesting, and some people find them useful. But in, in practice, for most people, it creates this kind of real anxiety, and that's where people can end up booing bananas in a, in a lecture theater, right? That's where people get too fixated on it and worried about things that actually, in the grand scheme of things, are not something you need to be worrying about. These are generally just, sorry to interrupt you. These are generally people with far too much time on their hands to think about their longevity, and they're not people who are living in the real world, but their influence is huge on all of us, right? Because they are the sort of top tier in terms of, uh, financials, and so we kind of w- emulate them, and we think that that's part of what got them to where they are. But actually, it's the years of them grafting and eating Deliveroo every night that got them to where they are.

    13. AAAli Abdaal1:31:22

        [laughs]

    14. SMSophie Medlin1:31:22

        It's not them focusing on hyperbaric chambers and all that kind of stuff.

    15. AAAli Abdaal1:31:25

        Yeah, these guys all have way too much money. [laughs]

    16. SMSophie Medlin1:31:27

        Way too much money and way too much time on their hands.

    17. AAAli Abdaal1:31:29

        Um, I was hanging, having a chat with my girlfriend last night, and we were, we were talking about sauna use, 'cause there's all this stuff around like, oh, heat shock proteins and heat shock therapy and all that, all that kind of stuff, and I was thinking, "Yeah, you know, you know, they say, like, on, on Huberman Lab, he says four times a day," and we couldn't quite remember h- like whether, whether, whether it was 13 minutes or 14 minutes or 15 minutes, and she made a very good point. She was like, "Well, if you don't go to the sauna at all, it does not matter at all-

    18. SMSophie Medlin1:31:52

        [laughs] Yeah

    19. AAAli Abdaal1:31:52

        ... like whether, whether you're, whether you're 55 minutes or 58 minutes. Just try and, like, get to the sauna at least once a week first, and then once you're at the point where you're going four times a week, then worry about the optimization."

    20. SMSophie Medlin1:32:01

        Yeah, sure. I mean, also-

    21. AAAli Abdaal1:32:02

        [laughs]

    22. SMSophie Medlin1:32:02

        ... just remember that, like, 99% of the population don't have access to a sauna, so, and they're kind of okay.

    23. AAAli Abdaal1:32:07

        Yeah. True.

    24. SMSophie Medlin1:32:08

        [laughs]

    25. AAAli Abdaal1:32:08

        Um, but I think it, it illustrates that thing which, like, I, I, I definitely have a propensity for this, where if I don't have 100% of the information, I'm gonna go 0% of the way.

    26. SMSophie Medlin1:32:17

        Sure, sure.

    27. AAAli Abdaal1:32:17

        And actually, I should just go 80% of the way and then worry about optimizing the final 20%.

    28. SMSophie Medlin1:32:21

        Yeah, yeah. And I think that's just generally really good advice, isn't it? It's like those small steps that you take are the things that last and that are easy, and if you try and sort of have it stack, that makes a massive difference rather than trying to overhaul everything and get too details oriented.

    29. AAAli Abdaal1:32:32

        Nice. Um, okay, loads of somewhat unrelated things which are all,

22. 1:32:36 – 1:35:01

    What’s the deal with protein shakes?

    1. AAAli Abdaal1:32:36

       I mean, obviously related to the gut that I wanna ask you about, so I'm just gonna shoot a bunch of questions your way.

    2. SMSophie Medlin1:32:39

       Okay.

    3. AAAli Abdaal1:32:39

       Uh, what's the deal with protein shakes?

    4. SMSophie Medlin1:32:42

       Uh, it depends on how you're taking them, what you're using them for, but most people don't need them. So most people get plenty of protein in their diet. If you're someone who is trying to build muscle rapidly and you're busy and it's difficult to get enough kind of meals in the day, then fair enough, you could use a protein shake. But it's really important to look for one that doesn't have emulsifiers and colorings and all this stuff in it, preservatives, because you're just causing yourself more problems for later. They've got these health halo that we talked about that people think it's really healthy because it's a protein shake, when actually it's probably, like, birthday cake flavored, and it's got loads-

    5. AAAli Abdaal1:33:08

       [laughs]

    6. SMSophie Medlin1:33:08

       ... of different things in it that you don't want in your body. So I generally recommend to people to either use a whey protein isolate or a pea protein isolate if they're vegan, and then you can blend that up with, like, some berries and maybe some kefir or some berries and some, like, oats, for example, and you can make yourself, like, a really healthy, really good-tasting protein shake that's still got the same protein structures in it, the thing that you really need for muscle building. But it's not gonna have any lactose in it, it's not gonna have any other a- additives in it and the things you're trying to avoid.

    7. AAAli Abdaal1:33:34

       Nice. Um, any particular brands that you recommend?

    8. SMSophie Medlin1:33:37

       Depends on how bougie people are. [laughs]

    9. AAAli Abdaal1:33:39

       Mm-hmm.

    10. SMSophie Medlin1:33:39

        So, um, The Organic Protein Company have a really great, uh, whey protein isolate with literally nothing else in it, uh, and so no emulsifiers or anything else, so that's a really good choice.

    11. AAAli Abdaal1:33:47

        Nice.

    12. SMSophie Medlin1:33:48

        But it's expensive.

    13. AAAli Abdaal1:33:50

        Okay, here's another thing I've heard. Uh, blending veg is bad because you lose a lot of the benefits of veg once it's in a blender.

    14. SMSophie Medlin1:33:56

        Sure. So when we, uh, blend anything, it's kind of a step towards processing it, right? But so is cooking and so is other things that we do that are fine for us. Um, we do lose some of the fiber structure, but we maintain all the nutrients. So if you're talking about kind of, uh, putting it in a blender and you have all of it, it's slightly different to if you're juicing something. You lose all the fiber if you're juicing something. But if you're just blending it, you maintain a lot of the, the food that your gut bacteria want. So you're still getting loads of good stuff from that, and there's no harm in doing it. The harm, well, not harm, but the problem that people run into is a bit like when we're talking about oranges and juicing. You can end up having way more fruit than you would normally have or be able to physically eat in a sitting. But blended up, you can just drink it super easily. So what I usually recommend people do is add some, like, spinach in there, add some kale in there, bulk it out with some veggies, and balance that out with some fruit so that it's kind of a bit more of a balance between fruits and vegetables.

    15. AAAli Abdaal1:34:41

        Hmm. All right. I'm gonna try and find a decent recipe for this stuff. So, like-

    16. SMSophie Medlin1:34:44

        [laughs]

    17. AAAli Abdaal1:34:45

        ... I can put some oats, put some pr- uh, organic whatever protein powder, some fro- frozen berries, some frozen veg.

    18. SMSophie Medlin1:34:52

        Yeah.

    19. AAAli Abdaal1:34:52

        Chuck it all in a thing.

    20. SMSophie Medlin1:34:52

        Stick some seeds in, stick some peanut, like, some mixed nut butter would be great in there.

    21. AAAli Abdaal1:34:55

        Oh, yes.

    22. SMSophie Medlin1:34:55

        [laughs]

    23. AAAli Abdaal1:34:56

        Perfect. Fantastic. Um, on the note of juices and blending and stuff,

23. 1:35:01 – 1:38:30

    The danger of juice cleanses

    1. AAAli Abdaal1:35:01

       what's the deal with juice cleanses and, like, celery juice and, like, this kind of stuff that people do?

    2. SMSophie Medlin1:35:09

       I mean, it's an absolutely terrible idea. All of it. So I've got a very good friend, Dr. Rachel Kent, who is, um, she's an amazing researcher at King's College, and she, her sort of journey, she, she researches the impact of health tech on our general wellbeing and, and lives. And she started that journey into doing that because she did a juice cleanse. She was just doing it for general health, she didn't wanna lose weight, but she just read that juicing was a really good idea. She cut everything out. She was doing, like, a bit of a detox type thing in inverted commas, and ended up in hospital with terrible kidney stones-

    3. AAAli Abdaal1:35:36

       Oh, God

    4. SMSophie Medlin1:35:36

       ... and was in intensive care with sepsis and everything because she'd followed this guy's juicing advice that she'd seen online, and realized that this was a disaster, and now she does amazing research into the impact of, like, calorie tracking and that kind of stuff on your general life. Uh, so juice cleanses are dangerous and worrying, and something that we definitely shouldn't be doing. Anything that kind of, uh, involves, let's say, the word detoxing, it's just nonsense. So if you do something like a juice cleanse, you're actually depriving your body of loads of really, really important nutrients, meaning it's gotta work much, much harder, and in that process of your body working much harder, it's releasing more things that we might consider to be toxic, like oxidative stress and that kind of stuff, because you're just not allowing your body to work in its normal way. You're making your liver work really hard, you're making your kidneys work really hard, and that means that you're producing more stress in your body, which is actually physically harmful to you. So I don't have a problem with people having a juice as part of their, you know, adding a few more vitamins into their diet and stuff like that, fine. But if you're doing, like, a juice cleanse or detox, really bad news. Terrible health consequences for lots of people, and absolutely no health benefits.

    5. AAAli Abdaal1:36:39

       Nice. Um, there seems to be a lot of advice on TikTok these days about the gut, gut tok.

    6. SMSophie Medlin1:36:44

       Hmm.

    7. AAAli Abdaal1:36:44

       What's your, what's your view on gut tok?

    8. SMSophie Medlin1:36:46

       I mean, I've not seen any good advice on gut tok apart from what me and the girls from the TV show have been trying to produce. [laughs] There's some really terrible stuff on there, including, you know, I think they call it, like, a chia shower, internal shower, that kind of stuff, where people are trying to flush themselves out of things, and it's a terrible breeding ground for, you know, a bit like Instagram is, a terrible breeding ground for terrible advice that can cause all kinds of trouble.

    9. AAAli Abdaal1:37:07

       What's, uh, what's going on with colonic cleanses and colonic irrigation as, like, a health fad?

    10. SMSophie Medlin1:37:13

        Yeah, like a really bad idea. So if we take colonic irrigation as an example, most people who are going for colonic irrigation will be going because they have some kind of digestive problem that they're worried about. So it might be that they're just feeling a bit bloated, or it might be that they've got a bit of diarrhea or constipation, so they're going to a beauty salon effectively to have colonic irrigation. And what happens in that is they pass a tube up your bottom and then introduce a lot of water into the bowel, and that essentially kind of flushes out all of the-- whatever's in your colon. Your colon's a meter and a half long, right? It's a big organ, and so actually it's got a lot of stuff in there that's supposed to be in there, stuff that's feeding your microbiome, bits of it that actually are your microbiome that you want to keep in there. They're really important. Um, but also, if you've got any gut symptoms, and then you fill your colon with loads of water and put it under pressure, you're at risk of perforation, right? Because the person who's a beauty person who does your colonic irrigation doesn't know, doesn't have the skills to find out whether actually you've got a bowel cancer or you've got something structurally wrong with your bowel that is causing those symptoms. Maybe your GP doesn't even have the skills to do that. You might have diverticular disease, where the structure is affected, and there's narrowings, and there's, like, bits of the bowel wall that are really vulnerable. Introduce a load of water into that environment, put it under pressure, perforations can happen really easily. There's absolutely no health benefits to colonic irrigation, but loads of reasons that everybody should absolutely avoid it.

    11. AAAli Abdaal1:38:29

        Fantastic.

24. 1:38:30 – 1:41:31

    Gluten free diets

    1. AAAli Abdaal1:38:30

       Um, a lot of people seem to be going on gluten free diets these days. What's the deal with gluten free diets?

    2. SMSophie Medlin1:38:35

       Yeah, super trendy, right?

    3. AAAli Abdaal1:38:36

       Mm-hmm.

    4. SMSophie Medlin1:38:36

       So about 1% of the UK population has celiac disease, so that's where gluten is physically toxic to your bowel wall. So it causes physical damage to the lining of the bow-- uh, bowel wall, and that's a, an autoimmune condition, so it's a generally inherited autoimmune condition. So in their case, gluten should absolutely be avoided at all costs, including, like, a tiny crumb of gluten that could be on a chopping board or in the same fr- fryer. So, you know, frying chips, and they've got-- had batter in there, then they can't have chips that are fried in the same thing. So those people have to be super, super careful with gluten. The rate of celiac disease hasn't increased over the last few years at all, but the number of people on a gluten free diet has increased exponentially thanks to people like Gwyneth Paltrow and other people who are promoting gluten free diets as, as some sort of health elixir. Of course, in reality, that's just a low carb diet through the back wall-- uh, back door, right? So people are like, "Oh, I've lost loads of weight on a gluten free diet." It's just 'cause you're not eating carbs anymore. That's the reason you've lost weight. It's not good for you. It's not helping you. Gluten is this tiny little protein molecule that never did anyone any harm, apart from this 1% of the population, but it's been completely demonized by the kind of wellness community. And this sort of has pros and cons for the celiac community, because now everywhere you go, you can get really good celiac products and gluten free products, right, which is great. When I first started working as a dietician, gluten free bread was horrendous, and you couldn't buy gluten free cake anywhere, and now everywhere you go has gluten free options. But it's also made shop owners, like restaurants and that kind of thing, less worried about it. So people think you're just on a gluten free diet 'cause you're being fussy, as opposed to having a true allergy. So they're not necessarily handling things carefully or doing it because it's someone who's got celiac disease. They're doing it because it's someone that they think is just on a fad diet, which causes all kinds of trouble for people who do live with celiac disease. So there are pros and cons to that. We see that in other allergies as well. So, like, there's a, a couple of instances of, like, vegan food trucks giving people dairy-- with dairy allergies anaphylaxis, because they're just not being that careful, 'cause they're just being-- they're trying to be vegan, but they're not careful with contamination. So people who have anaphylactic dairy allergy think it's fine, but actually it's not. So there's all kinds of trouble with that. But ultimately, again, no benefits to cutting out gluten, loads of downsides, including things like affecting quality of life. So cutting out gluten is not a good idea for anyone, and not necessary unless you have celiac disease. Or some people with IBS do struggle with tolerating gluten, but it's usually not just gluten. So what I find is people have cut out gluten, they're like, "Well, I felt a bit better, but it wasn't altogether better." And that's because there's lots of other things that impact symptoms in IBS that we can do as a clinical treatment diet.

    5. AAAli Abdaal1:40:56

       So would you suggest, like-- Would it be worth random person just cutting out gluten for a week and seeing, seeing what happens? Or is that, like, too much of a N equals one bro science thing?

    6. SMSophie Medlin1:41:06

       Yeah, I mean, not unless they have any symptoms, not unless they s- like massively suspect that gluten's causing them problems. And again, you know, if you have some gut symptoms, and you cut out gluten, you might feel a bit better, and then you might start to feel worse again. But the chances are it's not because it was the gluten in the first place, it's 'cause you changed your diet completely. So people might cut out gluten, and then they don't eat the burger, or they don't eat the pizza, or they don't eat the other things. So they feel better, but actually it's not because they cut out gluten, it's because they're not eating processed food in the same way.

    7. AAAli Abdaal1:41:30

       We

25. 1:41:31 – 1:45:56

    The impacts of cutting out dairy

    1. AAAli Abdaal1:41:31

       talked a lit-- We, we, we touched a little bit earlier on dairy, and kind of dairy is bad, and replacing milk with oat milk, almond milk, soy milk, all that jazz. Um, what-- I guess, what's the health side of things? And I guess some people have an a- sort of an aversion to dairy for the kind of animal cruelty side of things. So how do you balance kind of these things?

    2. SMSophie Medlin1:41:53

       Yeah, I think it's really important to recognize there are lots of different reasons for coming off dairy, for being a vegan, whatever it might be. And if those are ethical, or they are environmental, or they are for, uh, reasons of religion, for example, then obviously that's absolutely the right thing f- for you to do. And I would never want anyone to listen to this and think that I'm saying that you have to drink milk if it's really in, like, in congruence with your ethical beliefs or your religious beliefs for that matter, because obviously that would make you feel really unhappy and uncomfortable, and that's not the right thing for anyone to do. But if you're doing it for health reasons, there's absolutely no data to show that plant milks are better for you as a human than dairy milk. And in fact, all the data that we have to date shows that people who don't consume dairy have much poorer bone health. So people who are vegans have a much higher instance of bone fracture than people who are not vegans. We have this really interesting period in our lives, so up until the age of 30, we can continue to mineralize our bones. So all the minerals we take in in our diet can be soaked into our bones up until the age of 30. We call that our peak bone density. After the age of 30, it's basically downhill from there, [chuckles] and your bones then act as like a mineral store for your body for the rest of your life. So within our bodies, we always have to maintain a really careful band of how much calcium and how much magnesium and how much other minerals we have in our body, because they're essential for the contraction of our heart and the movement of our lungs and everything else. So, um, blood minerals will always be the same, and our body will either take those minerals from the foods that we're eating, or it'll leach them from our bones in order to make sure we c- maintain that really tight level of mineral control in our bloodstream, right? So- You could spend all of your early 20s, teens, not having enough dairy in your diet because someone on the internet told you to not to have it because it's not good for you or because of something you've seen and that f- it makes you feel uncomfortable, but you never reach your peak bone mass, and then every day after that, you're just depleting your stores, and so by the time you're 40, your bones could be really brittle. And we see this in children, so even if children who have, have to have an, uh, uh, even children who have to have a dairy-free diet because of dairy allergy, they'll never have as strong bones or be as tall as children who consume dairy as they're growing up.

    3. AAAli Abdaal1:43:58

       Hmm.

    4. SMSophie Medlin1:43:58

       So it has a direct impact on our bone health, and people say to me, "Well, people in China don't eat dairy and they're fine," but they eat, like, s- broth with bones in it, so they're constantly having different things in their diet that contain loads of calcium. We're talking about a Western diet-type population where we just don't have other good sources of, of bones, of calcium in our diet, and the matrix of, of minerals in dairy is really, really important for our bone health. But it's also one of our main, dairy has been historically and still continues to be one of our main sources of iodine, and iodine has an impact on your thyroid function, and we're seeing loads and loads of young people coming through with iodine deficiency and thyroid problems because they've cut out dairy. And again, I'm gonna say it again, the influencers who told you to don't have any, like, there's no consequences for them on that. It can, it, low iodine can cause infertility. No one's got any re- like, no one can come back on people that told them to do that. So dairy is a very useful food to consume in your diet, and if you have cut it out because you think it's healthier for you, you've been misled. If you've cut it out because you've watched documentaries about hormones in cow's milk as well, you've been misled in the UK because we have very different and very careful farming practices in the UK in compari- in comparison to America, where those documentaries are made.

    5. AAAli Abdaal1:45:07

       Um, so let's say someone is vegan for ethical reasons.

    6. SMSophie Medlin1:45:10

       Mm-hmm.

    7. AAAli Abdaal1:45:10

       What can they do to, uh, minimize the negative impact of not having dairy?

    8. SMSophie Medlin1:45:14

       Great question. So what they're going to be focusing on is making sure that all of their plant-based products are f- well, things are fortified with calcium, essentially. You also need to be taking supplements, so you need to be thinking about iodine supplements, you need to be thinking about B vitamin supplements. There's lots of things that you need to be adding in. But dairy, taking out dairy, dairy's got these nine really important nutrients that just are harder to find elsewhere. So if you are someone who has, like, a, a family history of osteoporosis, for example, you might want to think about taking some extra supplements, getting a bone scan regularly just to make sure you're not doing yourself any harm there. But fortified foods are important, and supplements are important, and making sure you're eating lots of plants that do contain calcium is really important.

    9. AAAli Abdaal1:45:52

       Cool. Uh, changing gears a little bit, uh, why are some people saying

26. 1:45:56 – 1:52:12

    Why are people saying seed oils are evil?

    1. AAAli Abdaal1:45:56

       seed oils are evil?

    2. SMSophie Medlin1:45:57

       Um, I don't know. I think they've just made it up. [laughs]

    3. AAAli Abdaal1:46:00

       [laughs]

    4. SMSophie Medlin1:46:00

       So there's, uh, some interesting rhetoric. I've not done any reading about this, so this is my intake, or my, this is my take on it. Um, there's some interesting rhetoric around how seed oils can have an impact, like a pro-inflammatory impact on our body, and as far as I know, there's no convincing data, and my, my amazing friends who are incredible researchers in lipids and stuff like that, they say it's all nonsense. So whatever they say, I go, "Okay, they know, they know way more about this than I do, and they're right." So there's no doubt- data to suggest that seed oils are having this kind of impact that people are worried about, um, as far as we know to date, and none of it's very convincing. What we do know is if we heat certain oils, they can have a more pro-inflammatory effect in the body, and that's why we think about things like, um, being careful with fried food, for example, because we know that can be less positive for us. We also think about, like, manufactured oils as just not being so good for us. So things like, uh, trans fats, they're called, so when fats are changed in structure from their natural form, which might be liquid at room temperature, to being solid at room temperature, they can make, like, a margarine. That kind of stuff isn't very good for us. Our body can't recognize it as being a natural thing, so it becomes less positive for us. So there are certainly things in that world that are true, but I think that the seed oils hype is, is not accurate to date.

    5. AAAli Abdaal1:47:10

       Nice. Um, just going back to the milk thing, uh, full fat, semi-skimmed, skimmed milk, which one?

    6. SMSophie Medlin1:47:16

       Do you know what? From a obesity perspective, there isn't-- What we see from the data is that people who consume whole milk generally have a lower body weight than people who consume skimmed milk, which is really interesting. There's lots of reasons that that could be, including that people who drink skimmed milk are the people who drink it because they struggle with their body weight, right, in the first place. So we don't know for sure. But actually, it seems to be that the minerals in dairy bind some of the fat and stop it from being absorbed as effectively, so we maybe don't access all of the fat from dairy, which may also account for, like, the French paradox stuff, where they eat a lot of cheese, but actually, they don't necessarily have higher le- level, they have better cholesterol levels than we do as a population. So there's some interesting stuff in there, but in general, we do recommend that people think about having lower fat dairy products. But I don't mean by that to have, like, fat-free yogurt that's got loads of sweeteners and other things and flavorings and stuff like that in it. I mean to try and keep things as natural as possible.

    7. AAAli Abdaal1:48:09

       Um, we've touched on the topic of calories quite a lot, but we haven't really, you know... What's your, what's your view on calories? [laughs] Very broad question.

    8. SMSophie Medlin1:48:18

       I mean, I think they've become this really, like, hyper-fixated thing, and actually it's just a unit of, of measure, right? It's just a unit of energy. It's just a physics thing. So calories in, calories out, we talk about a bit. It's just a unit of energy, how much energy you're burning, how much energy you're taking in. I think that they've become this, like, thing that we hyper-fixate on, and it's worth people remembering that labels for food are allowed to be up to 20% incorrect. So when you're using any kind of tracking app, actually it's gonna be at least 20% either side. So where people are going, "I've got 10 calories left, I'm gonna have one more peanut," actually, [laughs] that's complete nonsense, right?

    9. AAAli Abdaal1:48:52

       [laughs] Yeah.

    10. SMSophie Medlin1:48:53

        Well, yeah, but some people are numbers people, right?

    11. AAAli Abdaal1:48:56

        Yeah.

    12. SMSophie Medlin1:48:56

        And that's where they can get fixated on things, and it makes things worse for them ultimately mental health-wise and everything else. We know, like the almond story, you just can't, or the nut story, you just can't absorb all of the fat from nuts. So what it says on the label is not gonna be what you absorb from it. When we cook celery, it's got more calories than we don't cook it. All these things, like, have an impact on stuff because of how we can access the calories, and like, ultimately, if we could all go away from the calories and start thinking about are we physically hungry, that would be the best way to think about things. So if you're physically hungry, you should eat to your satiety And then you should stop eating until you feel physically hungry again, right? But most of us are making food decisions based on the fact that we're bored, or we're lonely, or we're tired, or we're having, like, an emotional reaction to something, so we want to eat. Or we're in a restaurant, and it's delicious, so we eat way beyond our fullness, all that kind of stuff. So the way that we work in clinic with these kinds of things is teaching people to listen to their hunger cues, listen to their body, trust their hunger hormones a little bit more, which is difficult work, and it takes a long time. But counting calories is counterintuitive to you learning to trust your body and having a, a, an, a healthy relationship with food for the rest of your life. So we never recommend calorie counting to anybody, because it can have this really undermining impact on your ability to listen to your hunger hormones and listen to your fullness hormones and all that kind of stuff.

    13. AAAli Abdaal1:50:10

        Hmm. So let's say someone does want to lose weight.

    14. SMSophie Medlin1:50:13

        Hmm.

    15. AAAli Abdaal1:50:14

        My-- And this is, this could be totally wrong, but I was under the impression that, oh, if I'm feeling hungry, it means it's working.

    16. SMSophie Medlin1:50:21

        Sure.

    17. AAAli Abdaal1:50:21

        [laughs]

    18. SMSophie Medlin1:50:21

        Yeah, yeah, yeah.

    19. AAAli Abdaal1:50:22

        Yeah.

    20. SMSophie Medlin1:50:22

        But, I mean, feeling hungry is not a good thing, is it? 'Cause when you're hungry, you're also really stressed and anxious. It's like a cortisol reaction.

    21. AAAli Abdaal1:50:28

        Yeah, I find myself watching a lot of food videos-

    22. SMSophie Medlin1:50:30

        Yeah. [laughs] Sure

    23. AAAli Abdaal1:50:30

        ... [laughs] when I'm feeling hungry at nighttime, thinking-

    24. SMSophie Medlin1:50:32

        Yeah

    25. AAAli Abdaal1:50:32

        ... it's gotta be done to get that-

    26. SMSophie Medlin1:50:34

        Yeah

    27. AAAli Abdaal1:50:34

        ... visceral adipose tissue down.

    28. SMSophie Medlin1:50:35

        Yeah, no.

    29. AAAli Abdaal1:50:36

        Yeah.

    30. SMSophie Medlin1:50:36

        You don't have to do that.
27. 1:52:12 – 1:58:45

    Is mindful eating helpful?

    1. AAAli Abdaal1:52:12

       To what extent is mindful eating helpful?

    2. SMSophie Medlin1:52:14

       Yeah, super helpful. Super helpful. So if you think about, um, sitting down with a small amount of food and consuming it mindfully, listening to your body, checking in. So the way that I might work this in practice would be, I would say you can have as much of this-- You're gonna make yourself a meal, and you can have as much of it as you want to have. But first I would like you to take away kind of a, you know, a smallish portion of it. Take it to the sofa. Eat it properly. Engage with it. Try not to have lots of distractions around you. Chew it properly. Take your time over it. And once you've finished it, have a little check-in. Am I feeling full? Do I want more? What, what do I feel like right now? If you still feel hungry, great, have some more. But if you don't, let's just pause there. Go and do something else. Distract yourself from the food. You don't need any more food. So it's about kind of tuning in, listening, chewing properly. All those things are really important as part of that.

    3. AAAli Abdaal1:52:56

       Sweet. Bit random, but I find that when I eat certain things, my belly bloats a little bit. It's not to the point of uncomfortableness, but it's just sometimes I wake up in the morning, and I, and I, I look down, and I'm like, "Oh, you know, you know, fairly flat belly." And other times, I wake up in the morning, like this morning, and I'm like, "Damn, how did I get so fat overnight?"

    4. SMSophie Medlin1:53:14

       [laughs] Yeah, sure.

    5. AAAli Abdaal1:53:15

       What, what's, what's going on there?

    6. SMSophie Medlin1:53:16

       So, uh, different foods ferment at different rates and produce different type-- amounts of gas in our colon. And when your colon, because it is a meter and a half long, it's a big organ, when it's full of gas, you look bigger. Then you might go for a poo and pass some gas, and you're kind of back to normal, right?

    7. AAAli Abdaal1:53:29

       Mm-hmm.

    8. SMSophie Medlin1:53:29

       One of the things that we see from this kind of Instagram culture stuff is that people think that these people are maintaining this very flat first thing in the morning belly all day long, when actually everything that you eat, especially if you're a very slim person, everything you eat is almost visible in your tummy. So you'll be aware of it, and you can see it if you carry a very low body fat percentage. So all of the models that are doing the posing are doing it first thing in the morning, and they're probably de-dehydrated and starved-

    9. AAAli Abdaal1:53:52

       Mm-hmm

    10. SMSophie Medlin1:53:52

        ... because that's when they look most ripped, as it were. Um, and actually, everything you eat has an impact, and you can see it. So yeah, it's normal. Normal to have a bit of bloating. And, you know, if you have a bit of bloating after eating beans and lentils and pulses and, like, garlic and onion and that kind of stuff, that's completely normal 'cause your gut bacteria love it, and they're fermenting it.

    11. AAAli Abdaal1:54:10

        There's nothing I can be, I can be like, "Oh, I look more bloated today, and I had avocado yesterday, therefore avocado's bad for me." Is, is there-

    12. SMSophie Medlin1:54:16

        Yeah

    13. AAAli Abdaal1:54:16

        ... any kind of bro science there that works?

    14. SMSophie Medlin1:54:18

        You, you can think about that. So things that are most likely to, um, to, to ferment in your gut are these, what we call fermentable carbohydrates, and the biggest culprits that we see in clinical practice are onion and garlic, pulses, apples and pears, and some of these kind of quite commonly consumed foods. So if it's something that bothers you or s- if it's-- certainly if it's causing you any pain, if it's something that's bothering you mentally or physically, it's worth going to see a dietician 'cause we can tell you exactly what it is that's causing it, and you can choose to avoid it on the days that you don't wanna feel bloated. But then you can go after it and eat whatever you like and be okay.

    15. AAAli Abdaal1:54:46

        Nice. Um, to what extent is glucose monitoring for glucose spikes useful?

    16. SMSophie Medlin1:54:52

        Great question. I mean, this is kind of outside of my area of expertise, if I'm honest. My experience of people monitoring their blood glucose is that they get very worried about things that are completely physiologically normal because actually our blood sugars are supposed to fluctuate during the day. They're supposed to go up and down. Your body has very good mechanisms of controlling your blood glucose. And if you're worried about an increase in your blood glucose that maintains it within the normal range, you're worrying about something that you should just be really happy that your body's doing that. You don't need to worry about the fact that that's happening. So I think it can-- it, it attracts people who are hyper-fixating on their health anyway, and it creates additional anxiety about everything they put in their mouth. So ultimately, I think it's really unhelpful, particularly in the long term. Might be interesting as a snapshot for a very short term under supervision with support, but I just don't think it's something we need to be encouraging people to do at all.

    17. AAAli Abdaal1:55:39

        So if, for example, I eat, I eat an avocado and it causes a, me more of a glucose spike than it does my mate- D- d- does that tell me anything about, like, my, m- the, the w- the way my body is, I don't know, absorbing avocado is different and therefore I should avoid them, or anything like that?

    18. SMSophie Medlin1:55:52

        It doesn't mean you should avoid them, no. It just means that you might want to think about combining them with other things that has less of an impact. I mean, avocado, just so you know, isn't gonna spike anyone's blood sugar.

    19. AAAli Abdaal1:55:59

        [laughs]

    20. SMSophie Medlin1:55:59

        [laughs] Um, but yeah, it's just something, it's a, banana is a better example, right?

    21. AAAli Abdaal1:56:02

        Yeah.

    22. SMSophie Medlin1:56:02

        So if you, you and your friend both eat a banana and it spikes yours more-

    23. AAAli Abdaal1:56:05

        Yeah

    24. SMSophie Medlin1:56:05

        ... are we talking about spiking you outside the normal range? In which case it's worth having a chat with somebody about that. Or are we just talking about increasing it slightly, in which case it's fine.

    25. AAAli Abdaal1:56:13

        Mm.

    26. SMSophie Medlin1:56:13

        Also, really worth remembering that a banana is not a standard food, same as an avocado. Like, they all are a different size and shape. If you eat a banana when it's more ripe, it's got more available sugar than when it's less ripe.

    27. AAAli Abdaal1:56:23

        Mm.

    28. SMSophie Medlin1:56:23

        And as long as your blood sugars are staying, rising and falling within the normal range of what we know to be healthy, you've literally got nothing to worry about.

    29. AAAli Abdaal1:56:29

        Nice. Do you, uh, do any research or stuff around things like, uh, the longevity side, like, you know, take, people taking metformin or statins and stuff even though they are, like, in their 20s?

    30. SMSophie Medlin1:56:40

        Yeah, I mean, there is some stuff around that. So when we developed the Smart Supplement, which is the multivitamin product for Heights, we had to unfortunately get a bit involved in that world, and it is, like, an interesting world. I think, you know, I know from my medical colleagues that some cardiologists just start taking statins to protect themselves from a very young age, even though they haven't got high cholesterol. But there's also real statin deniers in the low-carb community who are absolute charlatans and are causing all kinds of harm as well. Um, so it's a, it's a real mixed picture, but I think, ugh, metformin is slightly, you know, can have an impact on your liver and have some more complicated side effects for some people some of the time. So, you know, I just don't think people need to be taking any prescription medications unless they're clinically indicated, obviously. But there is interesting discussions around that world and protecting yourself from high blood, like, uh, insulin resistance essentially is what metformin's protecting you from, may have some benefits, but the side effects probably outweigh it. We don't have data on healthy people taking it and the potential side effects on that and what's better and what's worse, so I would avoid it.
28. 1:58:45 – 2:02:58

    Food and mood recommendations

    1. AAAli Abdaal1:58:45

       we kind of touched a little bit on kind of brain function and mood and concentration and things. I wonder if you could just sort of, you know, if, if someone was, was being like, "Hey, Sophie, how do I, how do I change my diet such that it improves my brain function or makes me hap- improves my mood?" What are, like, the top recommendations here?

    2. SMSophie Medlin1:59:02

       Yeah, great question. So, um, omega-3s are super, super important for our brain structure, as we've talked about, and they can also help to protect us from excess inflammation in the brain, which is linked to anxiety and depression and stuff like that. So either make sure you're having at least two portions of oily fish a week or take your omega-3 supplements. B vitamins are incredibly important for our brain health. They, they produce, they make things like serotonin, melatonin, all of our, they make dopamine, GABA, all of these really important brain chemicals that we really need all the time. So B vitamins are really essential for brain function, and we've got some really interesting work showing that you can use B vitamins in controlled circumstances in replacement of SSRIs, so anxiety and depression treatments, and they work in a very similar way in the right doses at the right moment for the right people. So B vitamins, super, super important for general brain function and brain health. And then we also think about things like antioxidants, and particularly the anthocyanins from blueberries are amazing for our brain health. So not just blueberries, but anthocyanins come in, like, red cabbage, other dark purple vegetables. And there's some amazing data showing that if children are given a blueberry smoothie before an exam, they perform better in that exam than the children who haven't had a blueberry smoothie. And then when we swap them over and the level of the exam stays the same, and the first children are given the blueberry smoothie, not given the blueberry smoothie, second children are, the children who had the blueberry smoothie always perform better than the children who didn't have the blueberry smoothie. So what we think is happening there is it's getting better blood to your brain, and that is meaning that you can have a better mental performance in a very, like, short p- like, period of time. So it's having that direct impact on your brain health in that moment. And so with the Smart Probiotic, uh, Smart Supplement, we've got B vitamins, we've got other things like iodine that are missing from people's diets that have a big impact, but we've also got vitamin D, which you really need for your brain health as well. I should have mentioned that. But we've got omegas, B vitamins, and anthocyanins as kind of the core components with the other essential things around it. And, I mean, I designed this, right? And then you, you do all the research and you put something together and you think, "Do you know what? I think that's gonna work really well given the research that we've got." But you always, always have this kind of sc- slight skepticism. And then when the reviews started coming in for it, I was like, "My God, it's really working for people." And it really works for me as well. I think with my ADHD and stuff, those nutrients are so important to me, and it really helps in terms of brain function for lots of people, and the reviews really kind of speak for themselves on that.

    3. AAAli Abdaal2:01:23

       Can we, uh, zoom into vitamin D? What's going on with vitamin D?

    4. SMSophie Medlin2:01:26

       Hmm. Sure. Everyone-- Just so everyone knows, everyone should be taking vitamin D in the winter months in the Western hemisphere, Northern hemisphere, sorry, because we just don't get enough sunlight. So the darker your skin, the less able you are to synthesize enough vitamin D from the sunlight. So the way that those studies are conducted are that people of all different skin colors are put in the s- Spanish sunshine in the summer for an hour at lunchtime, and they see who-- how much vitamin D is increased, and they can see that the darker your skin, the longer you need to be in the sun to synthesize the same amount of vitamin D, and the lighter your skin, the less amount of time you need to be in the sun to synthesize vitamin D. I'm a ginger, I synthesize more vitamin D than anyone else in the world. Uh, superpowers. So vitamin D is really, really important for loads of different things. We think of it more as being like a hormone now rather than a vitamin, so we see it within that capacity, and it, it helps to protect us from cancer, it helps protect us from, uh, you know, it's really important for our immune function, it's really important for our brain health. Vitamin D is a really, really essential nutrient for all of us, and it speaks to how our society has changed now that we work indoors and we stay indoors all day, that, well, you know, such a huge percentage of the population are vitamin D deficient, especially at this time of year. So vitamin D supplements are super, super important. I take them all year round. I think everyone else should too, but it's-- the, the government recommendations are that everyone takes them between October and April.

    5. AAAli Abdaal2:02:39

       Hmm. What other supplements do you take?

    6. SMSophie Medlin2:02:41

       I take Heights, basically. That's all. [chuckles]

    7. AAAli Abdaal2:02:43

       Nice. Fair enough.

    8. SMSophie Medlin2:02:44

       Easy. Ticks, ticks the box. [chuckles]

    9. AAAli Abdaal2:02:45

       Um, okay, let's talk about how you develop these. But before we go there, uh, why do-- why is the word supplement often associated with the word scam?

    10. SMSophie Medlin2:02:53

        Yeah, I mean, because so much of it is. The industry is honestly the Wild West. And,

29. 2:02:58 – 2:19:30

    Developing the smart supplement for Heights

    1. SMSophie Medlin2:02:58

       uh, so I started working with the guys from Heights, I think probably about five years ago when I was still working at King's, and the-- I hadn't really realized what a mess the industry was as a whole. So it's a really complicated thing and a difficult thing to make a really good quality supplement product, so most people just don't bother. And worryingly, anyone could go to a supplement manufacturer, anyone with no qualifications at all, and say, "I want to put this much of this thing in a capsule," and they can make that and sell it, and no one's necessarily checking that and making sure that it's safe, it's the right quantities, it's suitable for everybody. It's like anyone can do it, and that's why we see all these influencers and stuff like that flogging supplements and, and all this sort of stuff because they can just make their own any day that they want to. It's, it's a really-- it's a real minefield. All of the ones that are on the shelves in shops and stuff like that, the quality of them is incredibly variable, even the more expensive ones. There's some really, like, really eye-wateringly expensive supplements now that I look at the formulation, I think, "Why have you put those things together? They don't work together. They're counteracting each other. They're all trying to do different things and fighting against each other." And that's because they've not had a dietician or a nutritionist there, a qualified nutritionist there formulating for them and trying to help them to make the right decisions about what's gonna work and what's not gonna work. We also have a problem with the supplement industry where something is trying to be right for everybody. So it's like, "This is, like, a supplement for men." And I'm like, "Well, what about-- is it for a man who does a lot of exercise or doesn't do any exercise? Is it for a man who has a sedentary job or an active job? Is it for a man who is in his seventies or in his thirties?" All different people, right, [chuckles] need different things. So it's kind of about tailoring these sorts of things to specifically what you're looking for. But it is a minefield, and there's also big population-level data to suggest that people who take supplements don't necessarily have better longevity or live longer or anything like that than people who don't, like it's-- we're talking about kind of A to Z multivitamin. But I think that's largely because lots of people histor- I mean, the quality of them has been terrible historically, but also people take them as like a-- they just think, "Well, if I take this, I don't have to eat fruits and vegetables. I don't have to do anything else, so I'm ticking the box." And actually, that's just not

Episode duration: 2:22:45