The No.1 Poo & Gut Scientist: If Your Poo Looks Like This Go To A Doctor! Dr Will Bulsiewicz

1. 0:00 – 2:16

   Intro

   1. SBSteven Bartlett0:00

      What I have here is a variety of different shapes and sizes of poop.

   2. WBDr Will Bulsiewicz0:05

      Yeah.

   3. SBSteven Bartlett0:06

      What does this tell us about our health?

   4. WBDr Will Bulsiewicz0:07

      Well, if your poop looks like this, to me that's grounds to talk to a doctor.

   5. SBSteven Bartlett0:12

      Dr. Will Bulsiewicz.

   6. WBDr Will Bulsiewicz0:13

      World-renowned gut health doctor... Who has a wealth of information on...

   7. SBSteven Bartlett0:17

      How we can improve our gut health through food and lifestyle changes.

   8. WBDr Will Bulsiewicz0:20

      We are currently living through an epidemic of gut health issues, and if we want to be healthy humans, we absolutely need a healthy gut microbiome in order to accomplish that. So let's break this down. First of all, microbes are invisible. On your thumb, there are as many microbes as there are people in the UK.

   9. SBSteven Bartlett0:36

      Really?

   10. WBDr Will Bulsiewicz0:36

       And gut microbes play a critical and essential role in controlling whether or not you suffer from depression because 95% of the happy hormone is produced by the gut. It controls your cognition, your memory, your energy levels. Your gut is the place where you are making decisions, and study after study after study shows us that when people eat more ******, not only do they empower the gut microbes, but also they lose weight, they're less likely to die of heart disease, less likely to be diagnosed with multiple different types of cancer.

   11. SBSteven Bartlett1:02

       No way.

   12. WBDr Will Bulsiewicz1:03

       Yes.

   13. SBSteven Bartlett1:03

       What about alcohol?

   14. WBDr Will Bulsiewicz1:04

       The science is clear. When we drink to the point of having a hangover, is that dehydration? Absolutely not. The issue is you have caused significant damage to your microbiome. But the gut is forgiving, and the choices that you make today, within 24 hours, will have an effect on your microbiome. I want people to eat a diet where they can eat as much as they want without restriction and still achieve their weight goals. And this is completely possible by consuming a diet that's...

   15. SBSteven Bartlett1:29

       Quick one. This is really, really fascinating to me. On the back end of our YouTube channel, it says that 69.9% of you that watch this channel frequently over the lifetime of this channel haven't yet hit the subscribe button. I just wanted to ask you a favor. It helps this channel so much if you choose to su- subscribe. Helps us scale the guests, helps us scale the production, and it makes the show bigger. So if I could ask you for one favor, if you've watched the show before and you've enjoyed it and you like this episode that you're currently watching, could you please hit the subscribe button? Thank you so so much, and I will repay that gesture by making sure that everything we do here gets better and better and better and better. That is a promise I'm willing to make you. Do we have a deal? Dr. Will, if someone just clicked on this conversation

2. 2:16 – 5:32

   Why Is The Gut Microbiome So Important?

   1. SBSteven Bartlett2:16

      and they've- they're deciding whether to listen or not, what would be the pitch to those people? What's the benefit if they stick around?

   2. WBDr Will Bulsiewicz2:22

      Welcome to a, uh, what I sincerely believe will be a life transforming conversation for you because the issue is that we are currently living through an epidemic of gut- of gut health issues. Um, if we look across the board, this is everywhere. And it's not just, you know, uh, digestion. This is so much more than that. We need this now more than ever, because ultimately if we want to be healthy humans, which to me is one of the highest goals that we should hold for ourselves, if we want to be healthy humans, we- we absolutely need a healthy gut microbiome in order to accomplish that.

   3. SBSteven Bartlett2:54

      What's your sort of academic professional background?

   4. WBDr Will Bulsiewicz2:57

      Oh gosh, where do we begin? Um, so, uh, I graduated from Vanderbilt University, uh, with a chemistry degree. That was my college. And, um, I went to Georgetown, which is one of the top medical schools in the country. I, um, spent three years at Northwestern as a re- as, uh, internal medicine resident. I won the highest award that they give while there. Then I was the chief medical resident, and I spent four years training as both a gastroenterologist in the hospital and also working on clinical research. So I didn't expect when I finished all this that I would be continuing to publish papers at any point in my life in the future. But now in my work with ZOE as their US medical director, I've been heavily involved in clinical research again.

   5. SBSteven Bartlett3:42

      You mentioned a big G word there. Gastroenterologist.

   6. WBDr Will Bulsiewicz3:47

      Yeah. (laughs)

   7. SBSteven Bartlett3:47

      What is that?

   8. WBDr Will Bulsiewicz3:49

      Uh, we are the specialists in terms of basically, like, the intestines, the gut. So if I were to summarize it, I would say guts and butts.

   9. SBSteven Bartlett3:57

      Guts and butts. (laughs)

   10. WBDr Will Bulsiewicz3:58

       Yeah. (laughs)

   11. SBSteven Bartlett3:59

       The conversation around the gut microbiome and the gut generally has exploded really since, what, 2000 and, what, 2006, 2007 time? Before then... I mean, to be fair with you, I think as far as I'm aware, and I'm not that close to doctors or hospitals or research, I've only started hearing about the gut microbiome in the prevalence that I have in the last two years?

   12. WBDr Will Bulsiewicz4:22

       Yeah.

   13. SBSteven Bartlett4:22

       Three years? What is the central misconception that most people have as it relates to their health? That guy that looks into the mirror and goes, "I don't like what I see here. I don't feel good." That's curled up. They're- they're bloated. They've got gut pains. The current sort of line of thinking will say it is X, but there's something that you believe it is. What is that?

   14. WBDr Will Bulsiewicz4:44

       Well, I think that all of these things ultimately con- connect back to our gut microbiome, and I think that's the piece of the puzzle that's been missing this entire time. You know, there's- it was sort of this black box. If you eat well, you will improve your health. If you do this, you will improve your health. Um, what we are missing was the understanding that all of those choices ultimately impact these gut microbes, and by impacting these gut microbes, you can actually transform the physiology within your body.

   15. SBSteven Bartlett5:10

       Gut microbes.

   16. WBDr Will Bulsiewicz5:11

       Yeah.

   17. SBSteven Bartlett5:11

       What is that?

   18. WBDr Will Bulsiewicz5:13

       Gut microbes is my nerdy way of talking about these, uh, microorganisms that, like, you can't see them right now, but they're there. They're, you know, if you hold up your thumb, literally on your thumb, there are as many microbes as there are people in the UK.

   19. SBSteven Bartlett5:29

       Really?

   20. WBDr Will Bulsiewicz5:29

       And they cover our entire body from the top of our head

3. 5:32 – 10:14

   What Are Gut Microbes?

   1. WBDr Will Bulsiewicz5:32

      to the tip of our toes. Every single external part of our body is covered with these microbes, but the main spot is actually deep inside of us, which is our colon, the large intestine. In that spot, you can find 38 trillion. Now these, when I say microbes, it's referring to the fact that they're microscopic and they're alive. It's mostly bacteria. Um, in addition to bacteria, could also be fungi, could be parasites, could be viruses. But we have 38 trillion of these mostly bacteria focused and concentrated within our colon. So when we talk about the gut microbiome, we're really referring to them.

   2. SBSteven Bartlett6:09

      How did they get there?

   3. WBDr Will Bulsiewicz6:10

      So, you started in your mother's womb.

   4. SBSteven Bartlett6:12

      Mm-hmm.

   5. WBDr Will Bulsiewicz6:13

      And evidence these days would suggest that you're already starting to come into contact with these microbes.

   6. SBSteven Bartlett6:19

      Mm-hmm.

   7. WBDr Will Bulsiewicz6:19

      But, um, but for the most part, you haven't really met them yet, until the water breaks. And in that moment, for the first time, you are exposed to the world, and the world is covered in microbes. Everything that's alive, everything, has a microbiome. Could be a plant, could be an animal, could be an insect, could be us. So when mom's water breaks, these microbes then enter into the uterus, and you meet them for the first time, but you are particularly exposed to them as you pass through the birth canal. And this is basically like nature's way of being like, "Hello. Welcome to the world, and meet your partners. They'll be with you for the rest of your life. And they're here to help you, and they will make you healthier." And this is the result of co-evolution that goes back over a billion years. We have been evolving, and, uh, which is crazy because humans have only existed for three- three or four million years. But these microbes were the first life on the planet, and all life evolved with these microbes. And things like, for example, our immune system is the product of evolution that started a billion years before humans even existed.

   8. SBSteven Bartlett7:34

      We always think of ourselves as one organism, but you're making the case that I'm maybe 36 trillion, or whatever you said, organisms-

   9. WBDr Will Bulsiewicz7:40

      Yeah. (laughs)

   10. SBSteven Bartlett7:40

       ... in one.

   11. WBDr Will Bulsiewicz7:42

       And we would call you a superorganism. And that sounds like a Marvel character.

   12. SBSteven Bartlett7:45

       (laughs)

   13. WBDr Will Bulsiewicz7:46

       Which is cool and we'll take that, but that's actually completely true because the issue is that if we withdrew these microbes from you, if you were, like hypothetically... Well, you know, we could talk about the Bubble Boy from, um, the 1970s where they actually did this. They tried to have a child live in a sterile world, because he had a specific immune deficiency. So their thought was, "If we keep him separate from all the bacteria, then he'll never have a problem." But the issue is that there are consequences, there are consequences to living without microbes, because we need them. So, and it- through this process of co-evolution, literally from the very first human, we grew to trust them, and we trusted them with things that are critically important to us and our success as humans, and we allowed them to integrate into our physiology in a way where, once again, if we don't have them, we're in trouble. And that includes things like digestion, breaking down our food, which to me is like, that's the essence of life, like you can't get energy into your body without this. And they help us to accomplish that, but they also train our immune system. You know, we talked a moment ago about what happens when you're born, and that's the very beginning of training your immune system, and during those first three years of life, it has a massive impact on whether or not you develop allergic issues, autoimmune issues down the road. They affect our metabolism. Our researchers at ZOE has overwhelmingly shown that they play a critical and essential role in controlling, for example, your blood sugar, your blood fat response after a meal. They affect your mood. Um, literally your energy levels, uh, whether or not you suffer from depression, your cognition, your memory, your ability to focus, all affected by these microbes. They affect our hormones. So in women, conditions like endometriosis, polycystic ovary syndrome, associated with damage to the gut microbiome. In men, erectile dysfunction, which, I mean, to be honest, is not talked about enough, um, perhaps because we've stigmatized this. But this (laughs) - the guys that have this issue, this is like the most important issue to them. And so when you think about all these things, whether it be digestion, our immune system, our metabolism, our hormones, our mood, our brain health, like, to me, this is, um, uh, an overview of everything that matters for human health from my perspective as a medical doctor.

   14. SBSteven Bartlett10:13

       And is my gut microbiome

4. 10:14 – 13:35

   Everyone's Microbes Are Different.

   1. SBSteven Bartlett10:14

      different to yours, uh, or do we all have different sort of jungles inside of us?

   2. WBDr Will Bulsiewicz10:20

      We are all different, and this is one of the things that makes us actually profoundly different. So to be honest (laughs) , it's- it's- this is mind-blowing. If we looked at your genetic code-

   3. SBSteven Bartlett10:31

      Mm-hmm.

   4. WBDr Will Bulsiewicz10:31

      ... and my genetic code, even though clearly we are different people, we- our genetic code would be 99.99% the same. It's a small part of our genetics that is different between us as humans, but our microbiome, these 38 trillion microbes that are living inside of us, they can be completely different. So as- as a classic example, let's pretend that you have a twin brother, identical twin brother.

   5. SBSteven Bartlett10:59

      Mm-hmm.

   6. WBDr Will Bulsiewicz11:00

      All right? So you share the exact same genetic code, you share the same mother. For the vast majority of cases, you would have shared the same childhood and largely the same upbringing and food and things like this. And our research shows that only about 25% of your microbes would be shared, even though you come from the exact same place. You would be 75% or more different. So you and I, it's hard to say exactly. Like if our diet was, you know, quite similar, then we would have a more similar microbiome, but it still would be more different than the same.

   7. SBSteven Bartlett11:27

      And how much then... So I've got a twin, we've got completely different micro- gut microbiomes, so these sort of, um, microbes that live inside our bodies. How much of our microbiome can be associated back to disease and things like that? In your view, what percentage of disease do you think links back to the gut microbiome?

   8. WBDr Will Bulsiewicz11:48

      Well, it's hard to say globally, right? It's hard to give an exact number. Um, you would have to, I think, go condition by condition to say. But what I would say is this. My- You know, the reason that I became very interested in this as a gastroenterologist is that I was convinced, and I continue to believe this to be true, that every person that walked through the door to see me had a gut microbiome problem.... right? People with irritable bowel syndrome, Crohn's disease, ulcerative colitis, celiac disease, acid reflux, go down the line. Every single one of these, when we study them, we discover that they have gut issues. But the other thing, if you expand that, one of the things that I would always do, when I'm about to go see a patient, I'm gonna walk into the room and you take the chart off the door, right? You hear... If you're the patient, you hear that. You're in the room and you hear the chart come off the door, and the doctor flips it open and what do I do? I take a look at their medical history. And when you, uh, when you look, what you see is a laundry list of conditions that have been associated with damage to the gut microbiome. So they're here to see me for their digestive problem, like irritable bowel syndrome. But when I take a look, I see that they have hyperlipidemia, high blood pressure, type 2 diabetes, history of major depression, uh, they may have a autoimmune condition, right? So, and then it starts to implicate these different systems that, like, we have not classically associated immune, like autoimmune issues or metabolic issues or cognitive issues or mood issues. We haven't classically associated those things with the gut microbiome, yet they are. And so to me, do I need a... like, for that particular patient, do I need a poop test to tell me that they have a damaged gut? Absolutely not. It's already clear.

   9. SBSteven Bartlett13:32

      And what's the relationship between our gut microbiome and our

5. 13:35 – 17:41

   Link Between The Immune System And The Gut.

   1. SBSteven Bartlett13:35

      immune system? Uh, I was reading in your ... the introduction to your book that 70% of the immune system is, is the gut.

   2. WBDr Will Bulsiewicz13:40

      Yeah. The, um, the walls of your intestine are actually the home of your immune system. We classically would think of the bone marrow as being the place where the immune system exists. That's not true, that's where the immunes- the immune cells are born there, but then they basically emigrate out and then they take up residence and live within the walls of your intestine. And by the way, this makes complete sense from an evolutionary perspective, because our gut is actually the most vulnerable part of our body. This is where we come into contact with the outside world. Your skin, you may think of that, no, your skin is a wall. Your gut is the place where actually you are making decisions. Do I absorb and allow this into the body or do I reject and keep it outside? And in order to help facilitate that, yes, we need our immune system there, but the other thing that we need is we need a barrier. We need something to basically, um, uh, section off the inside of the intestines and keep things separate. So what we have is called the epithelial layer, and this is quite humble. Like given how important this is in our body, it is just a single layer of cells that are being held together by this kind of cement called tight junctions. They stick together, on one side is 70% of your immune system, on the other side are 38 trillion microbes. And when this barrier breaks down, this is how things that are inside your intestines can get access to your body, um, get into your bloodstream, potentially cause a whole body infection, and then the immune system is forced to react. And when this is like we have an infection, s- uh, that's really important, we, that we... This is why we have an immune system to protect us in that setting. But what's happening in the 21st century, what started in the 20th century is chronic inflammation, and chronic inflammation is the result of a broken barrier. When that gut barrier breaks down, now we are giving access to our body to things that aren't supposed to get access, and the result is that the immune system stays perpetually active because it is constantly trying to clear stuff out because the barrier is broken. And for those who are wondering, "So, Dr. B, then how do we, how do we fix the barrier?" Not to put the question into your mouth, Steven, but-

   3. SBSteven Bartlett16:04

      No, please do. (laughs)

   4. WBDr Will Bulsiewicz16:06

      ... the answer is the microbes. The answer is the microbes because they are the stewards of the gut barrier. They help to repair it. Every three or four days, you actually completely transform and recreate your gut barrier. So it's not the one that you were born with, it's the one that you developed in the last three or four days, and you will turn that over. And when it turns over, we need these gut microbes to help us to form a strong gut barrier. So because it's constantly turning over, this is where the microbes come in and they're, and they're critically important.

   5. SBSteven Bartlett16:36

      Again, the microbes, when you s- when you reference microbes, you're talking about the bacteria, the yeast, the parasites, the viruses that exist in our, in our guts, and how long do they live for? You said they turn over in three days, does that mean that they live for three days typically?

   6. WBDr Will Bulsiewicz16:47

      So the, uh, the gut barrier turns over every three days.

   7. SBSteven Bartlett16:51

      Yeah.

   8. WBDr Will Bulsiewicz16:52

      Yeah. So, and those are human cells, so those are not the microbes.

   9. SBSteven Bartlett16:55

      Okay.

   10. WBDr Will Bulsiewicz16:55

       They... Okay, so those are your human cells keeping the microbes separate from your immune system and your body.

   11. SBSteven Bartlett17:01

       Mm-hmm.

   12. WBDr Will Bulsiewicz17:02

       Um, these microbes, they are, um, turning over, like literally every 20 minutes.

   13. SBSteven Bartlett17:08

       They're dying every 20 minutes?

   14. WBDr Will Bulsiewicz17:09

       So, well, not necessarily dying.

   15. SBSteven Bartlett17:11

       Replicating.

   16. WBDr Will Bulsiewicz17:11

       Replicating.

   17. SBSteven Bartlett17:12

       Okay.

   18. WBDr Will Bulsiewicz17:13

       Right? And so if we think about this, if we had, if you had one microbe in your intestines right now and we feed it something, whatever it may be, good thing, bad thing, whatever, 24 hours from now, that microbe will have spawned at least 1,000 new microbes. So if you think about the power that exists there to amplify choices, starting with one and ending 24 hours later with 1,000, it's crazy.

   19. SBSteven Bartlett17:39

       There's this really interesting

6. 17:41 – 25:46

   Foods To Improve Gut Health

   1. SBSteven Bartlett17:41

      sort of reframing in the introduction of your book, which is really simple, but it does cause you to... I think it's a really powerful frame to think through about h- what we eat and how we eat, which is where you say that, um, each of us consumes an average of 1.3 kilograms of food per day. Keeping the math simple, that's 475 kilos of food per year, meaning we'll consume about 36,300 kilos of fo- food during our lifetime. And in contrast to the couple of milligrams of medicine-

   2. WBDr Will Bulsiewicz18:11

      Right.

   3. SBSteven Bartlett18:11

      ... that we take, it really makes you realize that food is, in fact-... the medicine that we're feeding our body at all times. We think, we sort of compartmentalize food over here as this energy source that quenches hunger, and then we have medicine over here to fix stuff.

   4. WBDr Will Bulsiewicz18:25

      Yeah.

   5. SBSteven Bartlett18:25

      But in fact, y- you're doing 36,000 kilos of food in your lifetime, so the, the thing that's having the biggest sway on your medical, your sort of, uh, physiological health and your, your, your gut health is, of course, the food.

   6. WBDr Will Bulsiewicz18:39

      Yeah.

   7. SBSteven Bartlett18:39

      The food is the medicine.

   8. WBDr Will Bulsiewicz18:40

      Well, and I think that there's two t- important takeaways from that, 'cause there was a study, actually, that changed my life in 2014 that came out. Um, this was published in the journal Nature, which is literally the top journal on the planet, and, um, uh, the author was Lawrence David from Duke University. And y- you have to understand, if we go back, this is almost 10 years ago, in this moment, we didn't know if food changed microbes in humans. We didn't know this. This is new information. We knew it in mice, but it's not the same. Mice are not humans. Um, so what they did to try to prove this is they put people on, uh, diametrically opposed diets, so a completely 100% plant-based diet versus a completely 100% animal-based diet. It was only a five-day study, which is interesting because within five days you can actually see massive results. And the key, one of the key takeaways from this study is that the choices that you make today, within 24 hours, will have an effect on your microbiome. In that study, when they changed a person's diet, 24 hours later you could already see things underway shifting. So now, the other thing to keep in mind here is, uh, that I think is really important is the gut is forgiving. I mean, to a degree you can only beat it up so much.

   9. SBSteven Bartlett19:57

      Mm-hmm.

   10. WBDr Will Bulsiewicz19:58

       But the gut is forgiving. So this doesn't mean that there are foods that are on the table and off the table. Everything is on the table. But what we want is we want to create a way or a disproportionate consumption of those high-quality foods because when we do, we are lifting these microbes up.

   11. SBSteven Bartlett20:15

       Explain that process of food and the impact it has on the microbes. So is it like watering certain microbes? Is that a way to think about it in simple terms?

   12. WBDr Will Bulsiewicz20:25

       These microbes are as alive as you and I are, Steven, and we need to eat. Um, if I don't eat, I get quite hangry and they do too. And, but it turns out that the reason that they took up residence, 'cause they could've been anywhere, they could've stayed inside soil or lived on a plant or something like that, they chose to live inside of you. And the reason why they are inside your colon is because they get access to nutrition. You do that for them. You go out, you find food, and you deliver that to them. Whatever goes into your mouth, whatever it may be, it will come into contact with these microbes and they will consume it and, and this becomes their energy source. Because they're alive, they need energy. So but the choices that you make impact which microbes get to eat. So not every single microbe likes kale. Not every single microbe likes sugar. But there are some that like sugar and some that like kale. And when you make these choices, whatever it may be, those choices ultimately are going to feed specific families of microbes, lift them up, and allow them to thrive. So when we talk about, you know, improving dietary quality and you hear me talk about this in Fiber Fuels, which is a message that I started sharing publicly back in 2018, um, and the book came out in 2020, or if you listen to Tim Spector who published the paper that I'm about to talk about, um, the science is clear. The way to lift the microbes up is by eating a variety of plants. Now, in Tim Spector's paper that originally came out, it's called The American Gut Project, but by the way, the British Gut Project was a massive and critically important part of the study. In that study, um, you have to understand, the magic number that they came to was 30. A lot of that had to do with just the technique that they were using to measure. It doesn't mean that 29 is bad and 30 is fantastic. It's all on a spectrum.

   13. SBSteven Bartlett22:22

       30-

   14. WBDr Will Bulsiewicz22:22

       30 different plants per week.

   15. SBSteven Bartlett22:24

       Mm-hmm.

   16. WBDr Will Bulsiewicz22:24

       Yeah, 30 different plants per week. So the key is we want varieties of plants and every single plant choice ultimately is fuel for a healthy gut microbiome. So that's fruits, vegetables, whole grains, seeds, nuts, and legumes. It's not just veggies, it's not just kale. And to me, like, one of the things that I've always tried to do, whether it be as a medical doctor or as an author, I wanna meet people where they are. So, like, if it were, if I were consulting with you, I wanna know where you stand right now, and then we're gonna set realistic goals. 'Cause, so for a person who's eating 10 different plants per week, which by the way is more than I was eating 10 years ago, to go to 30 instantly, that would be quite hard. And when it's hard, it's more likely to become unsustainable. I would go from 10 to 15, and when you hit 15, I would be celebrating.

   17. SBSteven Bartlett23:12

       How many plants does the average person eat in the western world? America, the UK, Europe? Do you know?

   18. WBDr Will Bulsiewicz23:18

       Uh, I believe in The American Gut Project, the number was around 10 to 15 for the average person. It was a minority of people that were hitting 30 per week in that study.

   19. SBSteven Bartlett23:28

       It's interesting, when I, I did my ZOE test, I got my results back, and it d- did say that I had quite a narrow gut microbiome in comparison to my partner. And I was thinking about this. I was like, "You know, whenever we go somewhere, whenever we go to a restaurant, she orders new things-"

   20. WBDr Will Bulsiewicz23:44

       Yeah.

   21. SBSteven Bartlett23:44

       "... all the time." And if you look at our fridge, it's like tahini and this and all this, like all these plants, especially in the top part of our fridge. It's all f- like fermented stuff. She eats like she's a, like a rabbit or some- she just eats anything and she eats diverse food and she orders new things. And then there's me.

   22. WBDr Will Bulsiewicz24:00

       (laughs)

   23. SBSteven Bartlett24:01

       I like what I like. And if I go to a restaurant, anyone that's been to a restaurant with me like three times could order for me because they know... (laughs) Um, until I got my ZOE results back and it was, it was pretty alarming 'cause she had, her microbes were like a, like the Amazon rainforest-

   24. WBDr Will Bulsiewicz24:17

       Nice.

   25. SBSteven Bartlett24:17

       ... and mine were like, you know, a park at the end of a street.

   26. WBDr Will Bulsiewicz24:20

       Ugh.... you know? I think that it's important to start with food that you like.

   27. SBSteven Bartlett24:25

       Yeah.

   28. WBDr Will Bulsiewicz24:25

       We're all like that, what you described. But the issue is finding that motivation to push yourself. To me, this is the, this is the piece of the puzzle. Like again, this was a black box, we didn't know anything about the gut microbiome. We just had, like, nutritional ideas being tossed at us. Now this is filling in the gaps where it's like, "Hold up, no, nutrition affects the microbes, the microbes affect us as humans." Now we can connect those dots. And to me, I find this very empowering and motivating to know that that exists and to know that those choices, every single meal is an opportunity to follow this concept and add more diversity to your plate. But the other thing is you mentioned that your partner is eating fermented food. That's a lost art. People have not been consuming fermented food in the Western world. And the research is quite clear and standing out at this point that actually there, um, was a fascinating study out of Stanford University, randomized control trial, the intervention was to add fermented food to the diet in people that had not been consuming fermented food. And what they found, eight weeks later, is that they had increased the diversity within their gut microbiome. What does that mean? If your microbiome is the park at the end of the street, adding fermented food, we can, we can make it into a jungle.

   29. SBSteven Bartlett25:39

       Give me some examples of fermented foods. And what is the fermented part? Like, uh, what does that mean?

   30. WBDr Will Bulsiewicz25:44

       Well, uh, first of all,

7. 25:46 – 33:13

   Fermented And Prebiotic Foods.

   1. WBDr Will Bulsiewicz25:46

      we, we mentioned that all, all life on this planet has a microbiome. So there was an interesting study where they analyzed the microbiome of apples and discovered that when you eat an apple, like you just grab an apple off the, uh, out of the fruit bowl, um, that apple has about 100 million microbes that are a part of it. So they're already there and those microbes have been a part of that apple's life, helping it to grow from a flower to a fruit. Okay. So, um, now these microbes, they are also involved in the life cycle of that apple. So when the apple goes to spoil, the microbes are the ones doing that. In fact, I would argue that when food spoils, I actually find that reassuring. If food doesn't spoil, we should be concerned.

   2. SBSteven Bartlett26:32

      Hmm.

   3. WBDr Will Bulsiewicz26:32

      The microbes are helping to facilitate that spoilage that takes place and that's because the earth is taking it back. It's this, it's the cycle of life, and it's gonna turn into dirt.

   4. SBSteven Bartlett26:41

      Hmm.

   5. WBDr Will Bulsiewicz26:41

      Right? Now, fermentation is where we actually grab that process and we control it, almost like a magician, we're shaping it. And what we're having is we're empowering certain microbes to protect that food so it does not spoil, and they transform it. So if you were to take a cabbage, um, you know, you don't need to do anything special to this cabbage. You literally just buy cabbage, perhaps at your farmer's market, chop it up, put it into a mason jar, pack it in there, and add a sea salt brine solution, a salt water solution, and you basically put this into, you know, a nice cool space, give it a week, you will have sauerkraut. Sauerkraut is not salty cabbage. It's tart, it's bitter, uh, it's acidic, um, it's delicious. When you make it yourself, it is completely different than the sauerkraut that I grew up on that came from a can, which was soft and disgusting. So this is what fermentation is, it's transformation. The microbes, specifically bacteria and yeasts, are transforming the food for us. And when they do this, they also are eating. So because they eat, they grow stronger and they multiply. So you are creating a food that is high in microbes, which we could call probiotics. It has been transformed to unlock the nutrition, which we could call prebiotics. Prebiotics are the parts of our food that actually feed the microbes inside of us. It's their food, prebiotics. And they are releasing new chemicals that can have beneficial effects on your body, which we call postbiotics. You find all of this in that one jar of sauerkraut. So that, to me, is a superfood. And it could be sauerkraut, it could be kimchi. Uh, pickles, like pickles are not meant to be a vinegar thing. By the way, vinegar is the product of fermentation. But pickles were never meant to be, hey, add cucumbers and some vinegar and call it a day. Cucumber, uh, true pickles are meant to be that you take the cucumbers, you don't skin them, you allow the microbes that are on the surface to do their job, and you put them into a salt water solution with some, you know, some dill, some garlic, black peppercorns, and a couple of days later, you will have a pickle.

   6. SBSteven Bartlett29:11

      I want to make sure I'm super clear on those three biotics that you mentioned. So prebiotics are the food for microbes, probiotics are the microbes themself, and then postbiotics are the compounds that the microbes make. Is that roughly accurate?

   7. WBDr Will Bulsiewicz29:31

      That's roughly accurate.

   8. SBSteven Bartlett29:32

      Okay.

   9. WBDr Will Bulsiewicz29:32

      And there's a minor caveat, which is that for these things prebiotic and probiotic, they have to have beneficial effects on humans in order to count.

   10. SBSteven Bartlett29:42

       Okay.

   11. WBDr Will Bulsiewicz29:43

       So we can't call it a prebiotic because it has just an effect on microbes. Sugar has an effect on microbes. It's not a prebiotic.

   12. SBSteven Bartlett29:52

       Ah, okay.

   13. WBDr Will Bulsiewicz29:52

       Okay? So, and the same is true for probiotics. Now, the original conception of probiotics that most of us have, it comes from a capsule, right? And the reason why we can call it that is because we have demonstrated through clinical studies that the specific types of bacteria or, or yeasts, in some cases, that you find in that capsule have been proven to be beneficial to humans.

   14. SBSteven Bartlett30:15

       So the prebiotic is a food, the probiotic is actually alive.

   15. WBDr Will Bulsiewicz30:20

       Yep.

   16. SBSteven Bartlett30:20

       And then the postbiotic is not alive, that's a compound that's produced by the things that are alive.

   17. WBDr Will Bulsiewicz30:25

       That's right. And the key with all of this......is the postbiotic. So, one of the... And, and these can be things that are completely beneficial and good to us as humans. An example of this are the short-chain fatty acids. Short-chain fatty acids are the product of consuming fiber or resistant starches, and they come into contact with your microbes. Again, you would not be able to get these if you were sterile.

   18. SBSteven Bartlett30:53

       Can't I just drink them in a can, postbiotics? Is there not a can of postbiotics that I can just drink?

   19. WBDr Will Bulsiewicz30:58

       Well, so they're coming out now with supplements that, um, are these postbiotics in some cases.

   20. SBSteven Bartlett31:03

       Mm-hmm. Okay.

   21. WBDr Will Bulsiewicz31:04

       And, uh, the issue that I've taken with them, and I've actually (laughs) discussed with some people within the supplement industry, let's not assume that that's going to do the exact same thing that eating a high-fiber diet is going to do. It's not the same.

   22. SBSteven Bartlett31:19

       So let's then talk about what happens with those. I'm assuming that the postbiotics, um, compounds are the things that have the heal- all the health benefits. So the reason why the gut microbiome is so healthy, the reason why these microbes are so beneficial, is because they produce postbiotics, and these postbiotics help our body in various ways.

   23. WBDr Will Bulsiewicz31:37

       Yes. So we, uh, mentioned earlier, we were discussing how we have this gut barrier that's key to protecting our immune system, and I had mentioned that the, the microbes are the stewards of that, of that barrier. It's the postbiotics, it's the short-chain fatty acids, butyrate, acetate, propionate, that are produced by these bacteria that builds the wall. When you want to build your wall and protect your body and reduce inflammation, you need more of this. Now, it's not... That's not the only thing that they do. Those postbiotic short-chain fatty acids also directly affect your immune system, directly affect your metabolism, cross the... get into your bloodstream, pass throughout your entire body, cross the blood-brain barrier. They have the ability to actually get access to your brain and can affect your brain. And we could talk about different ways that, that, that they can do that. But the point is that this is what, um, really matters, because the microbes produce these short-chain fatty acids, and then these short-chain fatty acids have healing effects throughout the entire body. And when we, when we see human studies looking at fiber consumption and showing us how beneficial fiber is to us as humans, the rea- I want everyone to understand, the reason why fiber is beneficial to us as humans is because fiber comes into contact with microbes and those microbes release short-chain fatty acids. That's what's happening.

   24. SBSteven Bartlett33:10

       Metabolism. Metabolism is the...

8. 33:13 – 35:39

   The Relationship Between Our Gut & Metabolism

   1. SBSteven Bartlett33:13

      I've been learning a little bit about metabolism recently. When people think of metabolism, they think of the speed in which I process my food. So people in society say, "I've got a high metabolism," which means they're probably gonna be quite skinny. A low metabolism means, you know, I'm probably gonna take longer to process my food. What is the role between, the relationship between my gut and my metabolism? And have I defi- I've probably defined metabolism wrong there. But what is the relationship?

   2. WBDr Will Bulsiewicz33:38

      Well, m- metabolism is basically dealing with the currency of energy, right? So, and it is the engine that drives us as humans. And so how do these microbes affect our metabolism? Well, we have, uh, researchers at ZOE looking at this directly, called the Predict 1 study. And in that, we were looking at, like, what is the thing that tells me, predicts what your blood sugar response is going to be to this food, or your blood fat response after a meal? And when you start to line these things up, they're individually different, they're not the same. But if you look at both of them, the gut microbiome plays an essential and critical role in each. So in other words, if we know what your gut microbes are, then that empowers us to be able to understand why you have high blood sugar, why you have low blood sugar. Now, if we wanna get super nerdy and detailed, into the weeds a little bit of how this is actually happening, it does come back in many ways to these short-chain fatty acids. They're not the only thing. We're, you know... In some ways, we're reducing it a little bit too much. So I just wanna be clear to everyone, there's other things going on too. But these short-chain fatty acids, they have the ability to basically activate certain receptors and cells that will f- basically, like, allow us to have more sensitivity to insulin, to reduce fat storage, to enhance fat burning. So at the end of the day, when we think about these sort of measures of metabolism, 'cause there's certain things, blood sugar response, blood fat, cholesterol levels, um, uh, visceral obi- visceral adiposity, mean- meaning, like, fat that exists around our stomach. When you look at all these things, the gut microbes play an essential role in regulating every single one of them, and the short-chain fatty acids tend to be the key.

   3. SBSteven Bartlett35:25

      Uh, I read in your book that 60% of poop is bacteria.

   4. WBDr Will Bulsiewicz35:29

      Yeah.

   5. SBSteven Bartlett35:30

      Which w- it just blew my mind.

   6. WBDr Will Bulsiewicz35:32

      Yeah, and I think that this is an important conversation to have, because we have stigmatized poop. We're not allowed to look in the bowl. We

9. 35:39 – 40:24

   What Your Poo Says About Your Health.

   1. WBDr Will Bulsiewicz35:39

      should be looking in the bowl. And the reason why is because if I were a cardiologist, I would come over and I would check your pulse, I would listen to your heart, and those vital signs would allow me to have an idea of how you're doing in terms of, like, just on a basic level, your cardiovascular health. All right? I'm a gastroenterologist. If I want to know the basics of what's going on with you and your body, I wa- I need to know how you're pooping and what your poop looks like, because 60% of it is microbial in origin. Because it is not just the excrement of your food. What your poop looks like allows me to have insights into your gut health, and we've actually proven this. We've actually proven this at ZOE, because what we found... We did a study called, um, Blue Poo, and we fed people blue muffins. It had a blue food dye.... and basically, it's quite simple. You eat the muffins, and then you wait to see when they show up in the toilet bowl. And based upon that time, which is basically your gut transit time, how long it takes for the blue dye to pass through your intestines, we could tell you, um, what's going on with your gut microbiome, we could talk about cardiovascular risk, we could talk about visceral fat, all quite simply tied to your gut transit time based upon eating a blue muffin. So these things, many of these, um, things that you and I are discussing today, whether it be the gut connecting to our metabolism, our immune system, or whatever it may be, we can connect them back to these simple measures, like what does your poop look like or, um, or how long does it take for you to have a bowel movement.

   2. SBSteven Bartlett37:28

      The gut transit time, that's super fascinating. I do want to talk about poop as well, but, um, the gut transit time.

   3. WBDr Will Bulsiewicz37:33

      Yeah.

   4. SBSteven Bartlett37:33

      That's the time it takes for a muffin to go from my lips to the toilet bowl.

   5. WBDr Will Bulsiewicz37:37

      Yes.

   6. SBSteven Bartlett37:38

      And is a high gut transit time better than a low one? And what is determining whether I have a g- a high gut... a good gut transit time or a not so good one?

   7. WBDr Will Bulsiewicz37:46

      Yeah. So gut transit time is a, um, uh, a personal measure of the health of this entire digestive system. The reason why you do the blue dye, by the way, instead of, like, eating beets or something like that, is that the blue dye, we have, like, clinically validated this. So this, this paper was published in the journal, Gut, which is the top European gastroenterology journal, and there's a couple specific time points that we can use to sort of cut off these measures. Um, the first is 14 hours. If you are less than 14 hours, that is very fast. The other is 58 hours. If you are more than 58 hours, that's very slow. All right? So you eat these muffins, and then you basically just record, when did they show up, and the average person is somewhere on the range of 24 hours or 48 hours, typically one or two days after eating the muffins, that's when you, you start to see this, and those are both considered to be normal. Now, if we were to break these things i- out into less than f- 14 hours, more than 58 hours, or, you know, these two sort of peaks at 24 and 48, what you start to see is that this is four groups, and these four groups, every single one of them is a little bit different in terms of their gut microbiome, a little bit different in terms of their gut diversity, and we can make associations between these things and what people are eating. So the high-fiber consumers are all showing up in the middle, which means normal, and the low-fiber consumers are the people that are showing up on the outside. And it brings us to one of the properties of fiber that's kind of fascinating, which is that whether you have diarrhea or constipation, there's only one thing that can correct both of those. Diarrhea and constipation are both fixed with dietary fiber. It helps to normalize our stool, bring it back to the middle. So in a perfect world, where do we want to be? We want to generally be pooping about once a day, so you want your gut transit time to be about 24 hours or less. Um, that being said, like, is a person unhealthy if it takes two days for this to show up in their poo? No, I wouldn't characterize them as being unhealthy. But I- I do think, like, this is one of the things that we can look at that's simple, it's f- it's nearly free, and, um, available for all of us to try at home.

   8. SBSteven Bartlett40:06

      So yeah. So you, you, you would assert that if someone's going to the toilet, you know, three or four times a day or more, then there's probably a fiber problem. There's... may well be a fiber problem, and if they're... n- you know, they're sort of chronically constipated, it's also probably a fiber problem at the heart of it.

   9. WBDr Will Bulsiewicz40:22

      Generally speaking, yes.

10. 40:24 – 43:58

    How Fiber Affects Your Gut.

    1. WBDr Will Bulsiewicz40:24

       Now, I will say that fiber is not as simple as I wish that it was, and, and the reason why I bring that up is that for a person who's low on their fiber consumption, um, and they may suffer with these issues, increasing fiber is hard for them. And many people don't feel well. If they go too hard too fast when they do this, it folds them over. They feel unwell. I was in the exact same spot 10 years ago. If I tried to eat, like, you know, chili with a bunch of beans, I was not happy, so I preferred to stay away from that. So the point that I'm trying to make about this, the reason why people struggle with fiber is because we are 100% reliant on our gut microbes to digest our fiber for us. We don't have the enzymes to break them down, to break down fiber. The gut microbes are doing it. So if you have a damaged microbiome and you never eat fiber, you are- you can't expect your microbes to be good at digesting fiber. Our microbes, they learn and they get good at the stuff that we allow them to practice. So when we start to add more fiber, the way that I recommend that people do this is to start low and go slow. That just means adding a little bit at a time slowly over, over the course of at least weeks, if not months. Um, and this is what allows your, your gut microbes basically to keep up and adjust to what you're doing.

    2. SBSteven Bartlett41:50

       What about fecal treatment? You t- said there that if our gut microbiome is damaged, um, it's not gonna be great at processing the fiber. So can't I just get someone's poop who has, you know, that 60% of their poop is th- the microbes and eat it, or do some kind of fecal treatment where I put it in my body?

    3. WBDr Will Bulsiewicz42:10

       So this is e- this is actually being done. Um, now, we've been doing fecal transplants where we would take from a donor and put it into a person for an infection called C. diff, and we've been doing this for more than 10 years. And it is fascinating. The studies with fecal transplants in humans have not been, um, as successful as they were for the C. diff-So, we would love to say that we could treat ulcerative colitis, which is inflammatory bowel disease, with a fecal transplant. Um, generally, it seems that we cannot, at least where we stand today. But there is something interesting that we found in one of the studies on this topic, which is that there was one study where... Again, these studies are small. Like, we need bigger studies to really fully understand this. There was one study where they did have a couple of people on, with ulcerative colitis who went into remission, meaning that their disease was no longer active, after a fecal transplant. And they asked the question, what was unique? And they found they all had the same donor. So, what we think is that there's probably specific donors for specific diseases that could actually potentially fix those issues because at their root, they are gut issues. I think that the future of fecal transplant is very promising. But the complexity of figuring out who are these donors, like, could I be a good donor for some specific disease that I don't even have myself and don't know anything about? Possibly. And this is what we have to figure out.

    4. SBSteven Bartlett43:56

       And how do these poop transplants

11. 43:58 – 54:42

    How A Poo Transplant Could Improve Health Conditions.

    1. SBSteven Bartlett43:58

       happen? Is it orally or is it some other way? Are they injecting this poop? Are they putting it up their butt? What are they doing with it?

    2. WBDr Will Bulsiewicz44:05

       There's a couple ways. So the classic is a colonoscopy. So the way that I always, I would always administer it is that the patient comes in for a colonoscopy. They're completely asleep. They're not aware of anything that's happening. And during the procedure, I basically release this stuff. It's a liquid. It's not as gross as it sounds.

    3. SBSteven Bartlett44:23

       So that's a tube up the butt?

    4. WBDr Will Bulsiewicz44:25

       The colonoscopy?

    5. SBSteven Bartlett44:26

       Yeah.

    6. WBDr Will Bulsiewicz44:26

       That's a tube up the butt.

    7. SBSteven Bartlett44:27

       Okay.

    8. WBDr Will Bulsiewicz44:27

       Yeah, that's a tube up the butt. Now, the new technology that's been emerging in the last few years is that they can actually dry out the stool, so they lyophilize it and put it into capsules. You have to take a ton of capsules in order to do this. But this is an alternative choice, is, like, you could start taking this. What I think would be interesting-

    9. SBSteven Bartlett44:46

       What if the capsule breaks?

    10. WBDr Will Bulsiewicz44:47

        Well, hopefully not.

    11. SBSteven Bartlett44:49

        (laughs) Do you know what I mean? I've had a couple omega, omega-3 capsules break, and it's a nightmare, so.

    12. WBDr Will Bulsiewicz44:53

        Oh, dear.

    13. SBSteven Bartlett44:54

        I just can't imagine trying to go like that with my teeth.

    14. WBDr Will Bulsiewicz44:55

        This is not where we want to be.

    15. SBSteven Bartlett44:56

        Yeah (laughs) .

    16. WBDr Will Bulsiewicz44:57

        Um, what, what we're transitioning towards, like, the past, was this big event. You had to come in, get a big procedure, colonoscopy. Well, to do that repeatedly is simply not sustainable. That's not realistic. Now what we're entering into is the possibility that you could do this every day. You could just take your poop capsule every single day.

    17. SBSteven Bartlett45:18

        God, I'd love to be the CEO of that company. That, that'd be so fun (laughs) .

    18. WBDr Will Bulsiewicz45:22

        I mean, I think that, I think that this is going to happen. We just need-

    19. SBSteven Bartlett45:25

        Really?

    20. WBDr Will Bulsiewicz45:25

        Yeah, but I think we need... The, the technology is there. The technology is there. So what do we need? We need to identify who are the proper donors for this, and we need to, uh, run the clinical trials to prove that it will work. But to me, this is a super probiotic 'cause it's not just... You know, most probiotics are just one single strain. Um, and they can be beneficial. I'm not disparaging probiotics in any way. They can definitely be beneficial. But what we're talking about is a new future where you're actually reconstituting a healthy microbiome. And Steven, on this topic, real quick, it is fascinating because some of the people who are in this space, they're worried about the way the world is going in terms of microbes, right? So there's been this concept that perhaps you've heard about where, which is that, um, there's, like, been this great, uh, extinction event that's taken place, right? Where many species of animals are dying.

    21. SBSteven Bartlett46:21

        Mm-hmm.

    22. WBDr Will Bulsiewicz46:22

        And, um, and they're gone. Microbial scientists are worried 'cause the same thing is happening on a microbial level. So if you were to compare our microbiome as Westerners to a person who lives in a more, uh, primitive environment in Africa, we have half the microbes that they do. And so what these scientists are doing is they're saying, "What if those microbes that you find in those people, what if we need them? What if we evolved and they're required for us?" So they're creating a bank where they're collecting these poop samples from, like, pr- uh, primitive tribal people and saving them in the event that it turns out that the only way back is to actually take the poop from these people and create super probiotics that would help to reconstitute our microbiome.

    23. SBSteven Bartlett47:16

        I'm so compelled by this idea that there's gonna be this range of supplements in the future that are just like poop capsules.

    24. WBDr Will Bulsiewicz47:22

        I don't think it'll be supplements though. I think it'll be completely regulated. Well, what I mean by that is there's a difference in regulation between supplements and, um, pharmaceuticals. And I don't think they'll have any choice but to regulate this on the same level that you would a drug.

    25. SBSteven Bartlett47:35

        'Cause in my head I have this idea of, you know, if this really takes off, people with great poop are gonna be, you know, expensive.

    26. WBDr Will Bulsiewicz47:42

        Dude, I think my stock is rising. Give me that ƒ50.

    27. SBSteven Bartlett47:45

        Yeah, I want some of your poop (laughs) .

    28. WBDr Will Bulsiewicz47:47

        All right, if you want my poop, you will have to pay for it (laughs) .

    29. SBSteven Bartlett47:50

        (laughs) Yeah, but it's gonna be expensive. If you only go to the... 'cause you're healthy, you go to the toilet once a day, it's gonna be like gold.

    30. WBDr Will Bulsiewicz47:56

        Um, and that's the fascinating thing. Poop is on the biggest comeback in the history of comebacks right now.
12. 54:42 – 59:25

    Calorie Counting.

    1. WBDr Will Bulsiewicz54:42

       you turn off fat storage and turn on fat burning.

    2. SBSteven Bartlett54:45

       It really does shine a light on this calories in, calories out thing because... Yeah, I mean, there's so many people, I've talked about this a few times, that just think you just have to eat below the required amount of calories for your body and you'll lose weight. But in that example, it proves that there's this other process going on that's gonna determine, I guess, is it how many of those calories go through or is it just-... how your body processes that energy?

    3. WBDr Will Bulsiewicz55:07

       Part of it is, part of it is thermogenesis, meaning fat burning.

    4. SBSteven Bartlett55:10

       Yeah.

    5. WBDr Will Bulsiewicz55:11

       Part of it is also what you poop out.

    6. SBSteven Bartlett55:14

       Okay.

    7. WBDr Will Bulsiewicz55:15

       They've actually found that people who have a healthier microbiome, they poop out more calories.

    8. SBSteven Bartlett55:20

       Ah, okay. Interesting. What do you think of the calories in, calories out thing? If someone comes to you and they say, "Uh, I want to lose weight, doc," and they say, "I've, I've heard this calories in, calories out thing is the answer, so I'm just eating less. I'm eating lots of pizza, but I'm just having less calories."

    9. WBDr Will Bulsiewicz55:37

       I don't, I don't like that, obviously. So to me, dietary quality is the key. Um, there's too many examples where dietary quality... So first of all, our weight is, our, our health is not entirely determined by our weight. Is it a major factor? Yes, it is. But there's so much more.

    10. SBSteven Bartlett55:54

        Mm-hmm.

    11. WBDr Will Bulsiewicz55:55

        So dietary quality, study after study after study shows us that dietary quality is crucial to the health of our microbiome and also to our global health, our longevity and our risk for disease. So to pretend that that doesn't matter would be completely false and inaccurate. Um, the idea that calories is the only thing that matters... Uh, what I do want to say is this. There is some truth to the concept that calories matter. There's absolutely some truth to this. If you reduce your caloric intake, you will lose weight. The problem is that your body will compensate by slowing down your metabolism and so then it puts you in a, in a predicament where you can't continue to do this, it's not sustainable, because that weight loss eventually will stop and then you will, uh, your appetite signals will grow so much that you will start to overeat. And then when you overeat, not only do you gain the weight back, you rebound.

    12. SBSteven Bartlett56:50

        Yo-yo.

    13. WBDr Will Bulsiewicz56:51

        You yo-yo and you go above where you were before.

    14. SBSteven Bartlett56:53

        Wow.

    15. WBDr Will Bulsiewicz56:53

        And the problem with this is that when people lose weight, they don't just burn fat. They lose muscle mass. Like, all weight loss is associated with a loss of muscle mass. When you gain the weight back, the muscle doesn't come back. You're just getting fat. So, so the issue is you end up less healthy than when you started. To me, what I want is I want people to eat a diet where they can eat as much as they want without restriction until they are full and still achieve their weight goals. And this is completely possible by consuming a diet that's high in prebiotics because we hear so much about, uh, Ozempic or Wegovy, um, which is semagluti- semaglutide. We hear so much about this, and it's a GLP-1 agonist. GLP-1 is a gut hormone that exists within our body and, uh, it makes us feel full. We can stimulate GLP-1 through our dietary choices. If you eat the right food, which is basically a high prebiotic diet, you will activate the GLP-1 and you will naturally feel full. And the result of this is that in the process of actually activating your normal satiety signals, you will consume less calories.

    16. SBSteven Bartlett58:14

        Satiety signals are basically hunger signals.

    17. WBDr Will Bulsiewicz58:17

        Hunger signals. So basically, like-

    18. SBSteven Bartlett58:19

        Feeling full.

    19. WBDr Will Bulsiewicz58:19

        Yeah, so the issue that we all have is that we eat an ultra-processed diet. An ultra, ultra-processed diet, number one, makes us ravenous, right? Like, we can't stop. We want it so bad. Number two, it doesn't activate those fullness signals. And so the result is when we eat an ultra-processed diet, we overeat, and then you feel like trash. You feel like trash for a couple of hours, and that is the result of you overeating. You've thrown yourself metabolically out of balance, right? Don't we all love the meal that tastes great, but you eat until you're full and you stop and actually feel energized and don't need to take a nap or drink an energy drink to compensate for what you just did? And that happens when we do this the, the old-fashioned way. By old-fashioned, I mean like prior to modern history when ultra-processed foods came into, uh, existence. If we go back to the old way of eating, you would simply eat until you activate these hormones, things like GLP-1, which, you know, is concentrated in this drug, or peptide YY. These are gut hormones that basically tell our body when to stop

13. 59:25 – 1:07:18

    Medicine For Losing Weight: Pros & Cons.

    1. WBDr Will Bulsiewicz59:25

       eating.

    2. SBSteven Bartlett59:25

       Everyone's going crazy about Ozempic. I keep h- hearing about this drug and I think Elon Musk recently said he had had it and I know a few other people that have, um, started taking Ozempic there. I would say, you know, they're... None of them are overweight necessarily.

    3. WBDr Will Bulsiewicz59:39

       Yeah.

    4. SBSteven Bartlett59:40

       Um, but they're doing it because it's now been framed as this kind of super drug...

    5. WBDr Will Bulsiewicz59:43

       Yeah.

    6. SBSteven Bartlett59:44

       ... which can help you drop weight super quickly by making you feel satiated.

    7. WBDr Will Bulsiewicz59:48

       Yeah.

    8. SBSteven Bartlett59:49

       What do you think of Ozempic?

    9. WBDr Will Bulsiewicz59:51

       Well, I come back to this. So first of all, let me say that for people who need it, it's, I'm glad it's there. Um, I don't think that the entire world needs Ozempic in order to be healthy.

    10. SBSteven Bartlett1:00:00

        Is there any side effects or...

    11. WBDr Will Bulsiewicz1:00:02

        A hundred percent. A hundred percent. First of all, digestive symptoms. Um, massive, uh, massively common digestive symptoms. But there's also long-term risks and many of which we don't simply know much about because people haven't been using the drug long enough for us to really fully understand what happens if you use it 'cause once you start using it, you're not gonna stop. If you stop, you gain all the weight back. So once you start using it, you're basically committing to however old you are, you're gonna be doing this for years on years, if, you know, decades. Um, we don't know what happens after a couple of years.

    12. SBSteven Bartlett1:00:34

        Isn't it kind of skipping a step in the process of developing the gut microbiome, taking Ozempic?

    13. WBDr Will Bulsiewicz1:00:40

        Yeah, I think that's the point is that if we... So, you know, if we look at our countries, the U.S. and the UK, um, there's a major fiber deficiency and I don't think... You know, I realize I'm out there pounding the drum on this, but I don't think this is talked about enough, perhaps because people don't think that fiber is sexy. But I think fiber is sexy because it's so crucial and important to our, to our health, and this is an example where this is 100% true. So, uh, 95% of Americans are deficient in fiber. The average woman is getting 15 grams of fiber per day-...she's supposed to be getting at least 25 in the US. The average man is getting 18 grams of fiber per day, he's supposed to be getting 38. That's a massive, massive deficiency. And the issue is that the fiber is what actually empowers the gut microbes, by the way, through short-chain fatty acids, the fiber is what empowers the gut microbes through short-chain fatty acids to release these gut hormones like GLP-1 and peptide YY. So my thing is this, 'cause again, like our health is not determined exclusively by our weight balance, there are other things other than that. Why don't we consum- try consuming these foods? The average American eats 10% of their calories from plants, fiber-containing food. What if we can make that 30% or 50%? I think that we would see a massive difference. There was a study that was done, it's one of my favorite studies of all time, by a, uh, a professor in New Zealand, his name is Andrew Reynolds, and he compiled all of the available data on fiber. What happens when people consume more fiber? Here's what happens. They lose weight, uh, they are less likely to have a heart attack, they're less likely to die of heart disease, they're less likely to have a stroke, they're less likely to be diagnosed with diabetes, they're less likely to be diagnosed with multiple different types of cancer, they're less likely to die of cancer, um, their blood pressure goes down, their blood sugar control improves, their cholesterol goes down. Okay, like, that's sitting there for us, available, all we have to do is make the dietary changes and again, what happens in that process is you consume more fiber, it comes into contact with your gut microbes, they release short-chain fatty acids and they have healing effects throughout your entire body. So to me, I agree with you, I think that we're missing this, um, this middle piece, and when we're reaching for something that's an expensive drug, it's very expensive, we're reaching for something that's an- an expensive drug and it has a very real risk of side effects and it also has risk in the sense that we just don't know what happens after you take it for a couple of years, um, I- I don't understand why we would do that when think of the benefits that I just listed by simply increasing your fiber intake.

    14. SBSteven Bartlett1:03:25

        I've so many conversations with my friends about various drugs that they're taking, performance drugs, Modafinil, Ozempic, et cetera, and when I speak to them, they, they're very passionate that there's no side effects on all- all of these sort of things that I consider cheating.

    15. WBDr Will Bulsiewicz1:03:43

        Yeah.

    16. SBSteven Bartlett1:03:43

        And I, and I have to caveat this because there are some people who are in a situation with diabetes or other cardiovascular issues, um, who can have their lives saved with some of these drugs.

    17. WBDr Will Bulsiewicz1:03:57

        Yeah.

    18. SBSteven Bartlett1:03:59

        But for the most part, the people that I know that are consuming these drugs aren't doing it for that reason, they're doing it for vanity reasons or for performance reasons where it's like taking a shortcut, and every shortcut, I believe, in life comes with a cost.

    19. WBDr Will Bulsiewicz1:04:10

        Yeah. You're talking like a doctor. You're talking like a doctor because basically what you're talking about is risk versus, uh, risk versus benefit, and the way that I think and every other doctor thinks about their patient is does the benefit outweigh the risk? But there is always risk in association with these drugs. And what makes me different from most other doctors, where I turned the corner in my career, is when I started to ask the- ask the question why are we waiting until we get to the point that we need to write a prescription for a drug? Why are we waiting until that point? Why are we not intervening in a much earlier point where we could transform a person's life and get them to a place where they never actually get this disease? Or if they get this disease, it's so much easier for us to control that. And this is, so to me, what I come back to is basically what you're getting at, is why would we, why would we take a drug if we could change our diet and our lifestyle and actually protect ourselves?

    20. SBSteven Bartlett1:05:04

        It's easier.

    21. WBDr Will Bulsiewicz1:05:06

        It is easier.

    22. SBSteven Bartlett1:05:06

        It's much easier.

    23. WBDr Will Bulsiewicz1:05:07

        Yeah, it is way, it is much easier, there's no doubt, but the problem is you pay a price for that.

    24. SBSteven Bartlett1:05:11

        And the price is unobvious, so you've got an easier option where the benefits are clear and the cost, the risk is unobvious. A- a- a logical human being would take that path if they can afford it.

    25. WBDr Will Bulsiewicz1:05:23

        I agree. The issue is that these are not the same things though, and what I mean by that is that, um, you have diabetes, okay? Hyp- like hypothetically.

    26. SBSteven Bartlett1:05:36

        Mm-hmm.

    27. WBDr Will Bulsiewicz1:05:36

        You-

    28. SBSteven Bartlett1:05:36

        I hope you don't,

    29. NANarrator1:05:37

        (laughs)

    30. WBDr Will Bulsiewicz1:05:37

        Yeah, I hope you don't.
14. 1:07:18 – 1:13:29

    What Your Poo Should Look Like.

    1. WBDr Will Bulsiewicz1:07:18

       like dance with my grandkids.

    2. SBSteven Bartlett1:07:19

       So let's close off on this subject of poop...Um, my team actually prepared some poop samples earlier on, because I was wondering, as a gastroenterologist-

    3. WBDr Will Bulsiewicz1:07:29

       Yep.

    4. SBSteven Bartlett1:07:29

       ... I wondered that if you could look at someone's poop and determine whether they have good gut health.

    5. WBDr Will Bulsiewicz1:07:33

       Yeah.

    6. SBSteven Bartlett1:07:33

       And if you can understand what's going on in their body just by how their poop looks, because poop comes in many shapes and sizes. So what I have here is a variety of different-

    7. WBDr Will Bulsiewicz1:07:44

       (laughs)

    8. SBSteven Bartlett1:07:44

       ... shapes and sizes of poop.

    9. WBDr Will Bulsiewicz1:07:46

       Yeah.

    10. SBSteven Bartlett1:07:47

        For anyone that can't see, well, look at the screen if you're listening to this podcast on Spotify or YouTube, um, different shapes and sizes of poop here.

    11. WBDr Will Bulsiewicz1:07:55

        Yeah.

    12. SBSteven Bartlett1:07:55

        This is real human poop.

    13. WBDr Will Bulsiewicz1:07:57

        (laughs)

    14. SBSteven Bartlett1:07:58

        So I'm gonna pass you that so you can play around with it.

    15. WBDr Will Bulsiewicz1:08:00

        Yeah.

    16. SBSteven Bartlett1:08:03

        And wh- why does the shape and size of our poop tell us anything? Why does it matter, and how is it indicating something that's pertinent to our overall health?

    17. WBDr Will Bulsiewicz1:08:10

        Well, because it goes back to what you mentioned earlier, which is that 60% of our... W- the, 60% of the weight of our stool is actually microbial in origin. So if you want a window into your microbiome, look at your poop. You don't necessarily need to go and do an expensive test, like quite simply looking at your poop is one of the ways that you can tell what's going on. So there was a study that was done in the '90s, so (laughs) a long time ago, and it was less than 2,000 people exclusively in the city of Bristol, and it led to the creation of a chart called the Bristol Stool Scale.

    18. SBSteven Bartlett1:08:42

        About here, I'll put it on the screen.

    19. WBDr Will Bulsiewicz1:08:44

        Yeah, (laughs) and we're gonna, we're gonna run through this. But before we do, I wanna mention a few things real quick as the US medical director of ZOE. I'm proud of my contribution as a gastroenterologist, as a physician, to the work that we're doing there, and we not only did the blue poo study, which we've talked about already, which is that you can eat your muffins and figure out your gut transit time, but we also did a couple of other things. One is called the Blue Poo Challenge, um, where we had over 20,000 people across the planet who were basically eating blue muffins and then reporting back to us on what was going on with them, and then more recently... So again, the Bristol study was 2,000 people exclusively in the city of Bristol. We recently did the largest study across the entire UK on poop and what people were doing in terms of their bowel movements. So it was called the Big Poo Review, and we had 142,000 people from across the UK basically fill out a 17-question survey, and part of what we were looking at was their Bristol stool form. We were also looking at how often they poop. By the way, the average person poops 1.7 times per day. Um, and we were also looking at, like how it associates with different conditions. So as an example, one in five people in the UK are constipated. One in six people in the UK have diarrhea. So it's interesting to take a look at all these things. So now getting into the Bristol stool chart, the uh, the dream-

    20. SBSteven Bartlett1:10:11

        That is, that is real poop. (laughs)

    21. WBDr Will Bulsiewicz1:10:12

        This is the... Uh, (laughs) it's lovely. Um, this is the dream. This is where we all wanna be, and this is a Bristol four. The Bristol four is the classic, uh, where I come walking out of the bathroom in slow motion and rock music is jamming and doves are flying in slow motion, and I just am such a stud.

    22. SBSteven Bartlett1:10:33

        (laughs)

    23. WBDr Will Bulsiewicz1:10:33

        So, and that's after a Bristol four. My wife knows what happens when I s- come out looking like that. It's soft and formed, okay, and it's like a sausage or a torpedo. Um, so pretty smooth. Now, um, when we move from a four to a three, a three is not that big of a deal, but it is getting some cracks and crevices in it, all right? So, and we're moving towards constipation. Now, a three, you know, a little more fiber, a little more hydration, some exercise. These are simple things that can help to get you back to a four if you're having one of these, a three. But that moves us to a Bristol two, where we are truly getting into constipation territory here. And basically what, this is like if you took a whole bunch of marbles of poop and jammed them together so it still forms into something, but it looks like a pack of marbles of poop that are stuck together. So that's a Bristol two stool. That's constipation. And then finally, a Bristol one is when you're having the rabbit, the rabbit pellets, and they're hard and they're not easy to get out, and sometimes they're a lot bigger than this. This is, these are sm- small. Um, so you would f- you would form this up into what would be like a golf ball, and that golf ball would be, uh, like a Bristol one.

    24. SBSteven Bartlett1:11:47

        Okay.

    25. WBDr Will Bulsiewicz1:11:48

        All right? You form it up into a hard ball like this-

    26. SBSteven Bartlett1:11:52

        Okay.

    27. WBDr Will Bulsiewicz1:11:52

        ... um, but perhaps even bigger, and it's actually hard for a person to pass this. It's so big, it's so hard, um, that your bottom has a, a problem relaxing to let it out. Okay, so Bristol one and two are forms of constipation. Let's go back to the middle. We're gonna start from five. The, the stool is soft. It's not hard. It's not lumpy/bumpy. It's soft. But it's starting to break into blobs, different pieces of poop. Um, so, and we're moving towards, uh, we're moving towards diarrhea, where, like, just, like, fragments of solid stool are a Bristol six, and then when it's just, like... Or the other thing, a Bristol six could be like a cow pie, um, where there's no form. It's just someone plopped down this formless patty. And a Bristol seven, finally, is straight liquid. Straight liquid.

    28. SBSteven Bartlett1:12:50

        And w- w- how is this pertinent to our gut microbiome, our health? What does this tell us about our health?

    29. WBDr Will Bulsiewicz1:12:55

        There's been now multiple studies, including our work at ZOE on the blue poop study, uh, that was published in the journal Gut. There's now been multiple studies where basically what they found is that if you can look at which of these Bristol types you have, it does give us some insights into your gut microbiome and what's happening there. So now, where do we wanna be? In a perfect world, we want to be somewhere on the spectrum of three, four, or five. We ideally want to be a four. You're not...... uh, unhealthy if you have a three or a five.

    30. SBSteven Bartlett1:13:26

        So if this type four poop, which is kind of like a sausage, it's kind

15. 1:13:29 – 1:16:32

    How To Have A Healthy Gut.

    1. SBSteven Bartlett1:13:29

       of like a smooth sausage-

    2. WBDr Will Bulsiewicz1:13:30

       Yeah.

    3. SBSteven Bartlett1:13:31

       ... is optimal, how does one do that? What is turning it into a type four? What are, what are they eating, doing?

    4. WBDr Will Bulsiewicz1:13:37

       Yeah. Interesting question. We, uh, one of the things that we found in the Big Poo Review, which is our nationwide survey of 142,000 people, we actually looked at what they were eating and we were able to find associations between fiber intake and specifically plant-based food intake and having a number four. So in other words, we found associations between fiber intake and basically plant-based food intake and having a number four. So basically what that means is the people that were having a number four bowel movement were consuming more, uh, legumes, whole grains, fruits and vegetables. The people who were having, whether it be a type one or a type seven, they actually were quite similar in terms of their diet, which is that, um, they actually were consuming lower amounts of fiber. Now, the other thing to look at too is, um, actually some studies have found that people who have more on the spectrum of constipation tend to have a higher fat diet, tend to typically consume more animal products, which of course are higher in fat. And people that are more on the, uh, loose or diarrhea side of things tend to be consuming more plant-based foods. So now you could have a very healthy diet and be having a Bristol five, and that actually is not problematic. And the reason that you're having the Bristol five is because you're consuming so much fiber that actually you're producing a lot of short chain fatty acids, and those short chain fatty acids, they're like lubricants for your poop.

    5. SBSteven Bartlett1:15:08

       And the gut transition time, how does that relate to these different types of poop? As you were saying that, I was thinking the one and seven, the type one and the type seven, the type one being those sort of hard nuts and the type seven being basically diarrhea, I was assuming that those are the poop types that would happen-

    6. WBDr Will Bulsiewicz1:15:26

       So-

    7. SBSteven Bartlett1:15:26

       ... with a lower and a super high gut transition time.

    8. WBDr Will Bulsiewicz1:15:28

       That's right. So a slow gut transit time, which is a gut transit time more than 58 hours, so again, we're... and this is all with the blue muffins. You eat the blue muffin, it comes out 58 hours later, you are more likely to be having a Bristol one or Bristol two, which is the c- classic constipation form. There's no way, no way that you would have slow gut s- transit time and have a Bristol seven. That's not possible.

    9. SBSteven Bartlett1:15:52

       A diarrhea?

    10. WBDr Will Bulsiewicz1:15:53

        Yeah. A diarrhea.

    11. SBSteven Bartlett1:15:54

        So diarrhea comes out fast and these sort of hard nuts, they take typically a long time?

    12. WBDr Will Bulsiewicz1:15:58

        That's right.

    13. SBSteven Bartlett1:15:59

        Yeah.

    14. WBDr Will Bulsiewicz1:15:59

        And the reason why this is happening, you know, um, so when water moves through the intestines, 'cause a ton of water moves through the intestines, and one of the jobs that our colon has, the large intestine, is to pull the water out. So the more time that something spends inside the colon, the more it's actually going to do that, pull the water out. This is the reason why when we have fast transit, it's high in water, and this is also the reason why when it's slow transit, it's extremely dry.

    15. SBSteven Bartlett1:16:29

        Okay, so that's the shape and size of a poop. But what about

16. 1:16:32 – 1:23:44

    Different Poo Colours And Health Conditions.

    1. SBSteven Bartlett1:16:32

       colors of poop? I've got some different colors of poop here. I've got some reds, some blues, some blacks, some greens, some whites, and some yellows.

    2. WBDr Will Bulsiewicz1:16:38

       Yes. (laughs)

    3. SBSteven Bartlett1:16:39

       How is color pertinent to health and everything we've been discussing?

    4. WBDr Will Bulsiewicz1:16:43

       All right, let's break this down. So first of all, why is our poop brown? The answer to that question has to do with bile. Bile is produced by our liver. It's actually involved heavily in digestion of fat. So, um, when we, for example, eat a fatty meal, our gall bladder will squeeze. People that have gall bladder issues know what I'm talking about. You eat a fatty meal, your gall bladder squeezes. Bile then mixes in your intestines with the food and the bile helps to absorb the fat. Um, that bile is what makes our poop brown. Now, that becomes particularly relevant if we're talking about a white poop.

    5. SBSteven Bartlett1:17:21

       People poop white?

    6. WBDr Will Bulsiewicz1:17:22

       Some people poop white.

    7. SBSteven Bartlett1:17:23

       No way.

    8. WBDr Will Bulsiewicz1:17:23

       Yes. And the reason why, uh, a person would have a white poop is if there's a blockage that stops the bile from mixing with their intestines. Um, on the flip side, uh, if you are struggling to process your fat, you could have a yellow poop. So... And this could be a person who has, like, a pancreas issue, for example, chronic pancreatitis. And so if they're not able to digest their fat, they have a fatty poop, it may come out yellow, and one of the things that they'll notice is that there may be an oil slick at the top of the toilet bowl.

    9. SBSteven Bartlett1:17:59

       Right.

    10. WBDr Will Bulsiewicz1:17:59

        That's fat. Oil is fat. So... All right, you've never had a... Have you ever had a green bowel movement?

    11. SBSteven Bartlett1:18:04

        None of your business. (laughs)

    12. WBDr Will Bulsiewicz1:18:07

        (laughs) Answer the damn question.

    13. SBSteven Bartlett1:18:09

        No, I haven't, no.

    14. WBDr Will Bulsiewicz1:18:10

        Okay. (laughs) Um, I have.

    15. SBSteven Bartlett1:18:12

        Oh, really?

    16. WBDr Will Bulsiewicz1:18:13

        Yeah. There's a couple reasons. Some are healthy, some are not.

    17. SBSteven Bartlett1:18:15

        All right.

    18. WBDr Will Bulsiewicz1:18:16

        So you could have a, um, you could have diarrhea, like from an infectious cause. Um, an example could be something called Giardia, which is a parasite.

    19. SBSteven Bartlett1:18:24

        Mm-hmm.

    20. WBDr Will Bulsiewicz1:18:25

        And that'll give you green poop. But you could also go too hard on the smoothies. I was drinking, like, 40 ounces of green smoothies a day and my poop would come out green. It was interesting. We're gonna... We're about to get into some that are really important. Um, before I do that, let me just mention real quick the blue. So the blue poo, um, you could get a blue poo from eating blueberries, um, particularly if you eat a lot of them. Uh, or alternatively, of course, this is the blue muffin, the blue poo challenge.

    21. SBSteven Bartlett1:18:51

        Mm-hmm.

    22. WBDr Will Bulsiewicz1:18:51

        So... And perhaps what we could do in the show notes is give people the recipe for how they can now go about doing that if they, if they're interested. All right, um, red and black. So we have to talk about... Let's, let's start with red, because of course red we think about blood. And, um, and I have a rule, which is that if you see blood in your stool, that's not normal, and to me that's grounds to talk to a doctor. And, you know, then there's different levels of intensity of how seriously we check it out, but, Steven, colon cancer, which can present with red stool...Um, colon cancer is the number two cause of cancer death in our countries. In the United States, 150,000 people are diagnosed per year. It's highly preventable, and it's shifting towards younger people. There has been a change in the last few years, in terms of colon cancer, where, you know, as an example, a person of, uh, your generation, you and I are pretty close I think, but I'm a little bit older, a person of your generation is four times more likely to be diagnosed with rectal cancer during their lifetime than my parents were, and twice ti- twice times more likely to be diagnosed with colon cancer compared to my parents' generation. So, there's been this shift, and it's also affecting younger people. So h- my point is this. Um, I've had patients who come to me, they go, "I saw a little bit of blood in my stool," do a colonoscopy, and discover that they have a massive polyp, which is a precursor to cancer. And by removing the polyp, we just basically stopped them from developing cancer. So, I take it seriously when you see a poop that is coated in red, all right? Now, that red may be just on parts of it, like it is here, where, uh, that's typically bright red coming from the bottom, so that would be either something in your rectum, could be hemorrhoids, could be an anal fissure, could also be a polyp in the rectum.

Episode duration: 2:04:14