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Dr. Sarah Berry: Why eating after 9 quietly grows belly fat

Berry shows snacking after 9 raises belly fat and inflammation: chewing slower drops calorie intake about 15 percent without changing what is on the plate.

Dr Sarah BerryguestSteven Bartletthost
Jan 27, 20252h 11mWatch on YouTube ↗

EVERY SPOKEN WORD

  1. 0:00 – 2:04

    Intro

    1. SB

      If you go on social media... "Seed oils are toxic. Seed oils are gonna give you Alzheimer's. Seed oils are gonna give you cancer." But I've done lots of research, and there is absolutely no evidence to show seed oils are harmful. Actually, they're beneficial for our health. And I'll come back to that, but the problem is that there is so much misinformation out there about what we eat, how we eat, and how it affects our health.

    2. SB

      So let's go into all of that. Dr. Sarah Berry is a renowned nutrition scientist and professor. With over 20 years of research, her work has reshaped how we think about food, metabolism, and gut health. Dr. Sarah Berry, we have a lot to get through.

    3. SB

      Yes.

    4. SB

      So let's start with the food matrix.

    5. SB

      That's so important because you can have two foods with identical labeling, same nutrients and calorie value, but can have entirely different impacts in terms of how you metabolize that food and how it impacts downstream health effects depending on how that food has been processed. Now, we also know the timing of when we eat is really important. For example, we found that snacking after 9 o'clock was associated with unfavorable health outcomes, the worst kind of fat around your belly, for example. This was even if you were snacking on healthy snacks.

    6. SB

      Really?

    7. SB

      And we also know that, on average, if you change the speed in which you eat your food by 20%, you'll reduce your calorie intake by about 15%. But where it gets really interesting is there's evidence to show if you chew your food 40 times versus 15 times, it can result in... And then there's the menopause. We've conducted lots of research, and one of the most exciting things is that there is principles which can reduce symptoms by about 35%. And so they are-

    8. SB

      This has always blown my mind a little bit. 53% of you that listen to this show regularly haven't yet subscribed to the show. So could I ask you for a favor before we start? If you like the show, and you like what we do here, and you want to support us, the free simple way that you can do just that is by hitting the subscribe button. And my commitment to you is if you do that, then I'll do everything in my power, me and my team, to make sure that this show is better for you every single week. We'll listen to your feedback, we'll find the guests that you want me to speak to, and we'll continue to do what we do. Thank you so much. Dr. Sarah Berry,

  2. 2:04 – 4:52

    Two Decades Studying the Impact of Food on Our Health

    1. SB

      can you give me a little bit of an overview over what you've spent the last sort of 25 years of your career focusing on and understanding?

    2. SB

      Yeah. So I've spent 25 years starting out in quite a specific area, looking at how diet impacts our cardio-metabolic health. So by this, I mean lots of factors related to cardiovascular disease, like type 2 diabetes, our cholesterol, our blood pressure, our inflammation. And then, uh, more recently, I've been looking at how actually we piece together all the complexity of who we are, what we eat, how we eat, um, into how that actually impacts how we respond to food and the healthfulness of a food. Um, most of my work's been done through running clinical trials, so randomized control clinical trials, where I recruit various people, get them to eat various things, do loads and loads of different measurements, and look at how a food or a nutrient or a diet might impact a particular health outcome.

    3. SB

      And how many of these individual pieces of our sort of health and lifestyle are you trying to piece together to form this picture? What are those pieces?

    4. SB

      The key pieces are who you are.

    5. SB

      Mm-hmm.

    6. SB

      So that's one of the key pieces. So by that, I mean your genetics, your microbiome, your age, your sex, your menopause status, all of those kind of things. The other is the food that you eat. And when we think about food, we need to think about it beyond the traditional way that we thought about food in terms of nutrients, you know, backpack labeling, fat, protein, fiber, carbohydrate. But actually thinking about food in terms of the fact that on average each food has 70,000 different chemicals, and these are contained within a very complex food structure, which we call food matrix, that modulates the impact that those chemicals and nutrients have. So that's the second thing that we need to think about. So we've got who you are, the food that you're eating, about the complexity of that food, and then how you eat your food. And by how you eat your food, I'm thinking about your lifestyle. I'm thinking about, are you jet-lagged?

    7. SB

      Yeah.

    8. SB

      How much sleep did you have last night? You know, what's the order in which you're eating your food within a meal or over the day? How stressed are you feeling? Um, when did you do physical activity? All of that also impacts how you will respond to food. And then I think the last piece of the puzzle is so important, that as nutritional scientists, I don't think we think about enough. Why do you make the dietary choices that you make? So why do you choose to have that for breakfast, for lunch, for dinner? Is it 'cause it's part of your culture? Is it because that's how you're just feeling emotionally? Is it because you're sitting with friends and it's part of that social experience?

    9. SB

      Mm-hmm.

    10. SB

      I think we're at a really exciting time in nutritional research because we're now able to collect data at a scale, breadth, depth, and precision that we've never been able to before that's allowing us to put together all of those pieces of the puzzle to start to see a clearer picture.

  3. 4:52 – 7:03

    What Is the Food Matrix and How Does It Affect Our Health?

    1. SB

    2. SB

      So let's go into all of that. Let's start with, um, the subject of the food matrix, which is a, a term I hadn't actually heard before, um, until today. What is the food matrix, and why, why do I need to know a- about that?

    3. SB

      So the food matrix, simply put, is the structure of food. And it's really important because we know that food is so much more than just the nutrients and chemicals it contains. So we know that food contains nutrients that people are very familiar with, like protein, fat, fiber, carbohydrate. We know that food also contains thousands of other chemicals. Many of these we call bioactives-

    4. SB

      Mm-hmm.

    5. SB

      ... that you'll have heard of, like polyphenols, you know, vitamins, minerals, et cetera. But they're all encapsulated within the structure of a food. So think of an apple versus apple puree versus apple juice. They're all coming from the same food-

    6. SB

      Mm-hmm.

    7. SB

      ... but they have a different structure. And the reason it's important is because we know that food structure modulates the healthfulness of the chemicals and nutrients within the food. And it's really, really relevant now. It's really relevant now because our food landscape has changed almost unrecognizably to 50, 100, 200 years ago. We're now eating a lot of food where the food matrix, the structure of the food has changed, and this is because we use multiple different processing techniques.

    8. SB

      So-In simple terms, if I were to zoom in on a piece of food on a microscope-

    9. SB

      Yep.

    10. SB

      ... the way that the f- the molecule of the food is put together is now different to what it used to be, and that's having an impact on my health?

    11. SB

      So in simple terms, it's that we are changing, often through processing, the structure of the food. Now by processing, it could be our own processing. When we chew a food, we change the structure. Take a nut, for example. You have a whole nut, you chew it, you break up the nut, it goes into your gastrointestinal tract, it's broken down further. We also change it using manual industrial techniques as well, so we use techniques like grinding, or we might use pasteurization for dairy, or, you know, e- extrusion for some carbohydrate-rich foods. We use all of these different techniques that also change the food matrix.

  4. 7:03 – 8:15

    Why Do We Need Processed Food?

    1. SB

    2. SB

      For better or for worse?

    3. SB

      It's a double-edged sword.

    4. SB

      Right.

    5. SB

      And I think this is what we need to remember, that everyone's demonizing at the moment, "Oh, it's processed food, you know, it's killing the nation. 60% of our energy is coming from, uh, processed food." Yes, we are eating too much unhealthy food, much of which has been heavily processed, but processing can also be used to our benefit. And we have to think, why do we even process food in the first place? Well, we process it to make it edible.

    6. SB

      Mm-hmm.

    7. SB

      I don't want to go and eat a rice grain that's not been cooked. We make it safe. I want to drink pasteurized milk because I know it's safer. We want to make it stable. Like, think how long a can can last for, and frozen vegetables versus fresh. So you're saving food waste. We want to make it taste good.

    8. SB

      Mm-hmm.

    9. SB

      Um, and we want to make it convenient. So there's all of these different reasons that we use food processing, but when we think about the healthfulness of a food, we need to think about it in terms of the processing techniques that have been used, as well as the nutrient composition. We can't look at them in isolation, in my opinion. And this is what I've done a lot of research looking into.

  5. 8:15 – 11:09

    When Is Processed Food Bad?

    1. SB

    2. SB

      And what is processing gone bad?

    3. SB

      (sighs) I think processing gone bad is when you've changed the nutrient profile of a food such that it is unhealthy, so in simple terms, it's too much saturated fat, too much salt, um, too little fiber, too little bioactives like polyphenols. A food that is very energy-dense, so you eat it really, really quickly, so you're eating too many calories, you're eating it before your hunger signals have got to your brain to say, "Whoa, Steven, you've had enough." And there's great research that has been looking at how processing can affect your eating rate, the energy density of food, the nutrient profile of a food, and that's where it can go wrong. But where it can go right is you can improve all of those things that I said, the stability, the safety of the food. You can also, um, increase the what we call bioaccessibility, so the availability of some of the nutrients within a food as well.

    4. SB

      Okay, so I've got some snacks over in the corner of the room here, which, um, I guess have been processed differently.

    5. SB

      Mm-hmm.

    6. SB

      To have a different impact on, on me as the consumer. Gosh, these look delicious. Mm-mm-mm.

    7. SB

      Oh, I hope they're salt and vinegar Pringles.

    8. SB

      (laughs) Are you gonna eat them?

    9. SB

      (laughs)

    10. SB

      Look at this. Oh, my gosh. Um, so I've got some mixed nuts here.

    11. SB

      Yep.

    12. SB

      And I've got some cookies, some little pieces of chocolate, and, uh, some crisps. So you were talking about this processing something so that I eat it faster.

    13. SB

      Mm-hmm.

    14. SB

      And then it doesn't, like, sort of satiate me or make me feel hungry. Crisps. We're a nation of crisp lovers. Um, when you were saying that, about something that makes you eat faster and not realize that you've even eaten it all, crisps were the first thing that came to mind for me.

    15. SB

      I love a crisp. (laughs)

    16. SB

      You love a crisp. We all love a crisp.

    17. SB

      So I think all of these first three foods, the crisps, the chocolate, the cookies, you know, i- if compared to what would be a healthy food, they've all got less fiber.

    18. SB

      Mm-hmm.

    19. SB

      They've all got, well, certainly the, the, um, chocolate and the cookie has got more sugar. Um, they won't have all of the wonderful bioactives in them. Um, and then with the crisps, depending on the type of crisp, it's probably quite high in s- uh, in salt. But the chances are with those three is that they are quite energy-dense, so they have quite a lot of calories per gram.

    20. SB

      Mm-hmm.

    21. SB

      Which is partly because of, uh, the processing techniques. Yet, if you take a whole food-

    22. SB

      Like these nuts.

    23. SB

      ... like a nut-

    24. SB

      Yeah.

    25. SB

      ... now, they're actually very energy-dense, so they're very high in fat. They're high in calories. But actually, because they're in their original food matrix, how your body handles them is quite different to if, for example, they had been

  6. 11:09 – 11:54

    How Long Does It Take for My Brain to Realise I’m Eating?

    1. SB

      processed.

    2. SB

      You, you mentioned something about my brain takes a little while-

    3. SB

      Mm-hmm.

    4. SB

      ... to figure out that I've started eating.

    5. SB

      Yep.

    6. SB

      So if I started s- smashing these crisps down now-

    7. SB

      Yep.

    8. SB

      ... how long would it take my brain to realize that I'd started eating, to sort of catch up and make me feel hungry?

    9. SB

      Yeah, so there's load- lots of different mechanisms that impact how full we feel, how hungry we feel, related to a food. There's different hormones that are released from different areas of our gut, for example, that feedback signals to say either you're full or you're hungry. On average, I would say it takes about 10 to 20 minutes for the fullness to really properly kick in.

    10. SB

      Mm-hmm.

    11. SB

      Now, you could easily have got through those. Well, I could easily have got through all of these-

    12. SB

      Mm-hmm. Before.

    13. SB

      ... in under that 20 minutes.

  7. 11:54 – 14:04

    Does the Food Industry Engineer Food to Be Highly Palatable?

    1. SB

    2. SB

      I wasn't aware that there was a delay, but it does make sense because there's certain foods that I used to eat like Pringles and snacks and crisps and things like that, where I feel like I could eat two chu- tubes of the thing before my body even, um, realized what was going on. And are they in some way designed to encourage that speed of eating and...?

    3. SB

      So there are many people who will say the food industry has specifically designed these...... to make them firstly, what we call hyper-palatable, so to have the right mix of fat, sugar, you know, carbohydrate, et cetera, to make them really tasty, and in this case, salt as well. Um, I don't think the food industry is out there to get us. I think that what the food industry were doing 50 years ago versus what they're doing now is quite different, but some people will say I'm very naïve. I do believe the food industry ultimately want to produce food that's safe, but also healthy for us.

    4. SB

      Mm-hmm.

    5. SB

      That's probably an unpopular opinion, but based on my interactions with the food industry, I believe that. However, I do believe that these crisps are there, have been made to be flavorsome, to be palatable to you, so that you do enjoy them. Now whether that's that you then go and overeat them, I think is, yes, a byproduct of that. Um, now, it's not, it doesn't take 20 minutes for all of the fullness signals to kick in, because as soon as you start chewing something, you start to release different hormones and different sensory characteristics of the food will also trigger some sort of fullness. But what we do know is that you have more of these fullness receptors-

    6. SB

      Mm-hmm.

    7. SB

      ... saying, "Hey, you're full," lower down in your gastrointestinal tract. And so if you can get food to the lower gastrointestinal tr- tract, that's when it says, "Hey, Stephen, you're full now." And these heavily processed snacks that you've got here would be typically absorbed higher up the gastrointestinal tract, 'cause kind of the hard work's been done. And yet when you've got something like a whole grain or a nut, typically that would be absorbed lower down the gastrointestinal str- tract, where you've got more of these fullness signals, so giving you that greater feeling

  8. 14:04 – 19:43

    The Importance of Eating Slowly

    1. SB

      of fullness.

    2. SB

      My girlfriend has said to me for many, many a year that I need to eat slower.

    3. SB

      Yep.

    4. SB

      And I thought it was like a spiritual thing that she's into, um, to do with like giving the food gratitude, et cetera, et cetera. But upon reading your work and having this conversation today, now I'm starting to believe that she was right all along, unsurprisingly once again, um, and that there is a- a- a scientific basis for slowing down how fast I eat.

    5. SB

      Absolutely. We now know that eating rate's important. There's some fantastic work that's being done by a Professor Keren Ford, who's dedicated many years into researching this, and looking at how changing the structure and texture of food can modulate your eating rate, and how also your eating rate can modulate, um, how you metabolize the food and how many calories you go on to eat. And so it's a great example. You know I talked about all of these different pieces of the puzzle, that's one of those pieces. So when we talk about how you eat, changing your eating rate, so how quickly you have your breakfast, your lunch, your dinner, or any of these snacks, will also, without you consciously thinking about it, change how many calories you eat, might change how quickly you metabolize the food as well.

    6. SB

      What's the sort of knock-on effects there?

    7. SB

      So, the research that's been done by Keren Ford shows that, on average, if you change the speed in which you eat your food by about 20%, you reduce your calorie intake by about 15%. And that's due to where you're releasing your hunger hormones, how many fullness hormones you're releasing, et cetera. So it's a really simple strategy, and we see this play out as well, even in our own evidence, when we look in our Zoe Predict studies at fast eaters versus slow eaters, we see that once we adjust for lots of other confounders, there's a difference of 120 calories between what fast eaters have over a day versus slow eaters, with the fast eaters eating more calories compared to the slow eaters. And there's even been clinical trials where they get groups of individuals and say, "Okay, slow down the rate at which you eat your food over the next, you know, three, four, five weeks." They have another group, they say, "Just eat at your normal rate." Those people who are intentionally slowing down the rate at which they eat their food lose more weight than those people who continue to eat at their normal rate.

    8. SB

      See, I always made this, like weird, unfounded evolutionary argument to her. I was like, "Well, you know, in the wild, you got to eat what you can-"

    9. SB

      (laughs)

    10. SB

      "... so people eat quick." But, um, we're not in the wild anymore, and the food choices that we have are drastically different now, so...

    11. SB

      Yeah, and also, the food that is available to many of us is the kind of food that can be eaten really quickly.

    12. SB

      Mm-hmm.

    13. SB

      So there's some great research that's been conducted that shows that heavily processed, soft-textured type food can be eaten 50% more quickly than the unprocessed, harder textured equivalent. So the kind of food that we're eating now is quite different. So you're eating it really quickly, you're overeating because your hunger signals haven't got there, but it's that rate at which you're eating.

    14. SB

      What's an example of a soft textured food versus like a hard textured food?

    15. SB

      So we can use a s- an example from a study that was actually conducted in 1977, and this was published in The Lancet. It was one of the first nutrition studies published, um, in The Lancet, and it's one of the first studies to show the importance of the food matrix, and it kind of got buried for many years. And this is a study by, uh, this scientist called Haber where he fed individuals whole apples-

    16. SB

      Mm-hmm.

    17. SB

      He fed individuals the equivalent amount of carbohydrate from apple puree. It was exactly the same, i.e. same nutrients, same fiber, same everything else in it. All that's different is the apples are hard, the puree is soft. And what he found was that those people who were given the puree, even though they were given exactly the same amount of calories, ate that puree, or rather drank that puree, three to four times more quickly than when they had the apples, the equivalent amount of calories. So they were eating the same amount of calories, but three to four times more quickly.

    18. SB

      That's like 300%, 400%-

    19. SB

      Yeah.

    20. SB

      ... faster. Okay.

    21. SB

      They felt less full, so when they measured their fullness, and they monitored that for quite a few hours, so going up to quite a few hours, those that were having the apples continued to feel full for longer. Those who were having the puree didn't feel full as long.And what also happened, interestingly, is those that were having the puree had what we call a blood sugar dip. So about two to four hours after having a high-carbohydrate meal, we know that some people have a dip in their circulating blood sugar. And we know from our own ............................ research that actually this can really increase your hunger levels.

    22. NA

      Yeah.

    23. SB

      And so we know from our research, if you are a dipper, I'm a dipper, hence I get hangry quite often. So in about two hours, I'm going to be-

    24. NA

      (laughs)

    25. SB

      .... eating one of these. If you're a dipper, you know, your blood glucose is going below your baseline levels, and so you get hungry (laughs) . You go on to eat 180 calories on average more at your next meal because of that. And so, I mean, this research from 1977 that I think is fascinating is that first research really demonstrating the importance of food matrix. And then since then, I've now, over the last 10 years, done lots of studies with nuts, with oats, for example, that demonstrate you can have two foods that have identical back-of-pack labeling, identical nutrients, identical calorie value if you were to look at the back-of-pack labeling, but can have entirely different impacts in terms of how much energy you absorb, how you metabolize that food, how it impacts your hunger, how it impacts downstream health effects.

    26. NA

      And you've done

  9. 19:43 – 26:15

    Research on Almonds and Why They Don’t Fully Break Down

    1. NA

      some research on walnuts, right?

    2. SB

      So we've done work on walnuts-

    3. NA

      Almonds.

    4. SB

      ... but particularly on almonds. So we've done lots of work with almonds, using it as a kind of proof in principle of the importance of the food matrix. Now, you just took a bite of that and I could hear the crunch.

    5. NA

      Mm-hmm.

    6. SB

      The reason I could hear the crunch is 'cause in almonds, like most nuts and like many plant-based projects, uh, products, um, there is a very, um, rigid cell wall. Okay, so that almond that you've, you're holding there has thousands and thousands and thousands of cells. These cells are tiny. They're about 50 microns. Okay? You can't see them with the human eye.

    7. NA

      (laughs)

    8. SB

      I can show you a micrograph. (laughs)

    9. NA

      Okay. (laughs)

    10. SB

      Um, but there's thousands in there. Now each of those cells, it's smaller than a grain of sand. And each of those cells is encapsate... Cell walls is encapsulating the fat. So we know that in most of these nuts it's about 50%, they're about 50% fat. Hence people say, "Oh, my gosh, I can't eat nuts, they're high-fat, they're high-calorie." Now, in all of those nuts, the fat's encapsulated in this rigid cell wall. When you bit that, you fractured some of those...

    11. NA

      Mm-hmm.

    12. SB

      ... cell walls. When you swallow it, you've chewed it, you chewed it a little bit, I assume?

    13. NA

      A little bit. Yeah, yeah, I didn't swallow it.

    14. SB

      When people chew it, we know from these lovely chew and spit studies or mastication studies that we do that at the point at which you swallow a nut, the particles, i.e. the size of the bits that you're swallowing that you've ch- you've chewed are about maybe half a millimeter to one millimeter in size. Now given that the s- cell within or of a almond nut is about 50 microns, that means when you're swallowing-

    15. NA

      Mm-hmm.

    16. SB

      ... within that what we call a macro particle, you've still got thousands of cells. They're intact. Where you've got this lovely cell wall containing all of this fat, and so you're swallowing these intact cells containing, encapsulating the fat. So they're what we call very low bio-accessibility. They're not very accessible to us, this fat. Now what happens as this passes through your gastrointestinal tracts, some of the enzymes can break down the cells a little bit, but actually a lot just comes out the other end. So I don't know whether you've ever eaten a bag of nuts and looked at your poo after?

    17. NA

      None of your business. I'm joking. (laughs)

    18. SB

      Okay. Go and do that. (laughs)

    19. NA

      (laughs)

    20. SB

      But you should see-

    21. NA

      (laughs)

    22. SB

      ... some almond particles.

    23. NA

      Really?

    24. SB

      You know, like when I'm... You know, being a mum, when I've, uh... I've looked at a lot of poo in my life through my work but also through being a mum.

    25. NA

      I bet.

    26. SB

      You can see whole nut particles in the poo.

    27. NA

      So nuts, are they just... Is it... They just don't break down fully?

    28. SB

      So they break down partially. So you break down about 10% in the mouth-

    29. NA

      Mm-hmm.

    30. SB

      ... before you swallow, so about 10% of the calories become available 'cause the calories are contained from the fat, et cetera. And then you probably break down about another 60 to 70% as it passes through your stomach, your small intestine, your large intestine. Okay? But you have loads of material arriving at your colon, which is your large intestine, that's undigested, which is good for two reasons. One, because you're giving all of this food to your microbiome, which we know is great for your health. Your microbiome's having a party with these nuts. But also, if you are worried about eating nuts because of their high calorie value, actually 20 to 30% of the calories are just coming out the other end.

  10. 26:15 – 29:00

    The Role of Fiber in Diet and Health

    1. SB

    2. SB

      And what role does fiber play in this? Because fiber's becoming quite popular now. They're, like, putting it in drinks and stuff like that. And I, I... There was some candy in America when we were recording over in, uh, New York whi- which had, like, f- it said, like, 15 grams of fiber added to this, like, candy.

    3. SB

      So fiber's a really interesting one and it's a really interesting one 'cause we know we're not getting enough fiber.

    4. SB

      Mm-hmm.

    5. SB

      So we should be getting at least 30 grams of fiber. In the UK, and it's similar in the US, we get on average about 20 grams of fiber. 95% of us are not having enough fiber. Fiber is the one nutrient that we know consistently is associated with beneficial health effects, reduce- reduction in many cancers, reduction in cardiovascular disease, reduction in levels of obesity, type 2 diabetes, et cetera. You know, it's an amazing nutrient, fiber, and we don't get enough of it.

    6. SB

      Just to pause there then, why is it so good for us? Because I mean, it sounds like a super molecule the way you just described it.

    7. SB

      So it's good for us for many different reasons and there's loads and loads of different types of fiber. And the different types of fiber are good for us for slightly different reasons. Really simply put, we've got soluble fiber, and that's great for us 'cause it impacts things like cholesterol absorption as well as other factors related to how quickly we metabolize food, et cetera. Then you've got s- uh, insoluble fiber which is the kind of fiber that, for example, are in those nuts because fiber in those nuts is actually the cell wall. So most cell walls in plants are just fiber. That's great for us because it's food for our microbiome, it helps bulk out our stool so reduces our transit time, how quickly the- o- our poo basically passes through our colon, reduces the risk of colon cancer and so forth. But largely because it is the food upon which our microbiomes have their party, produce all of these wonderful molecules that we know impact so much related to our health. But we don't get enough of it and we don't get enough of it 'cause we're not eating the right types of food that we have in high amounts. So having any kind of fiber is gonna improve our health. Having fiber that's added artificially back into food is going to be better than having no fiber. So the kind of bars that you're talking about that say, "Are added fiber," great. Having fiber though from the whole food is always going to be better. And so with nuts, fiber is essentially the cell walls of the nuts.

    8. SB

      Mm-hmm.

    9. SB

      So it's having that role in reducing that biaccessibility that we talk about, that slowing those nuts down. So that's always going to be better having that fiber in the whole food in its original structure in the way nature intended.

    10. SB

      Mm-hmm.

    11. SB

      But having any kind of fiber is better than having none. And in a nation or, or, you know, many nations where we're not having enough, if we can get some in our diet even if it is processed fiber, it's better than no fiber in my opinion.

  11. 29:00 – 32:51

    Cardiovascular Disease and the Link to Unhealthy Snacks

    1. SB

    2. SB

      One of the, um, big revelations in my household has been just getting some of these bad snacks just out the house and replacing it with, um, healthier whole snacks. And I say that because th- the sort of the very definition... The very, like, sort of use case where we snack is when we typically don't have a lot of time where the hunger kind of crept up on us in between a meal, um, and so we make fast decisions.

    3. SB

      Mm-hmm.

    4. SB

      It's not a var- a very considered decision. Um, and I was reading that there's been some studies done where they took sort of two groups and gave them typical snacks versus healthy snacks and they found a pretty significant reduction in cardiovascular disease?

    5. SB

      Yeah. So this is one of my studies.

    6. SB

      Okay.

    7. SB

      Um, and we looked at how changing people's snacks can impact their health. And the reason we're interested in this is because we're a nation of snackers in the UK, as in many countries, so we know that about 25% of our energy comes from snacks. That's phenomenal. And so what we wanted to do is look at if we do a really simple snack swap, can we improve people's health? And so we asked people to change 20% of their energy from either having typical UK snacks-

    8. SB

      Mm-hmm.

    9. SB

      ... or having 20% of their energy from almond nuts for six weeks. And then we looked at various health-... outcomes at the beginning of that six weeks and then at the end of that six weeks. We said keep everything else the same. We provided all of these snacks to them. We provided the typical UK snacks. We spent a lot of time designing these. (laughs) So we did lots of research where we looked in the UK, and it's the sa- very similar in the US, what are the typical snacks? So basically, we designed these muffins that ultimately were having a bit of a potato chip or crisp, a bit of a chocolate biscuit, a bit of a cake, just like imagine, all put in one muffin. I mean, we didn't go and get those and just-

    10. SB

      (laughs)

    11. SB

      ... stick them in one muffin. But we worked out what's the nutrient profile in the UK, in the US that comes from snacks, and then we designed a snack product that was quite highly processed that reflected that nutrient profile. So it's quite high in saturated fat, high in sugar, high in refined carbohydrate, low in fiber. People had to eat 20% of their energy from these muffins, which my kids loved.

    12. SB

      (laughs) Yeah, good.

    13. SB

      (laughs) Um, or 20% from the almond nuts. At the end of that, we measured lots of health outcomes. One of which was a particular measure that we do to look at people's vascular functions, so their blood vessel function. It's a measure called flow-mediated dilation. It tells us in really simple terms kind of how healthy the blood vessels are. And what we found was the improvement in blood vessel function following having almond nuts versus having typical UK snacks equated to a 30% reduction in cardiovascular disease.

    14. SB

      That's crazy. In, in what period of time?

    15. SB

      Six weeks.

    16. SB

      In six weeks?

    17. SB

      And do you know what I think's really interesting about this is it's one simple single dietary strategy, and snacks are under our own control, typically.

    18. SB

      Mm-hmm.

    19. SB

      I, what I have as a snack isn't determined by my fussy kids. What I have as a snack quite often isn't determined where I am at that point in time 'cause I can bring my snacks with me. It's a really simple single dietary strategy that can have a big size effect, and I think that that's real important. It is real important though, Steven, at this point that I do say that I have actually had funding from the Almond Board of California, and they did fund, uh, that study, although the way we conduct our RCTs, the funders have no impact over the study design or, you know, they don't get to see the raw data or, or the paper before we're publishing it. But I just think it's always important to declare conflicts of interest. We've seen this though play out in other studies with other nuts or other snack substitutes, so it's not unique just to almonds. It's a great illustrator of how changing our snacks can improve our health.

  12. 32:51 – 36:55

    Is There a Knock-On Effect From Having One Snack?

    1. SB

    2. SB

      And we, we really are a nation of snackers. Um, you highlighted one of the stats there that in the UK and in the US, about 25% of our energy comes from snacks. 75% of the energy that's coming from those snacks is coming from unhealthy snacks. This was taken from the ZOE podcast. Uh, in Meditration- in Mediterranean countries, only 14% of energy comes from snacks, which is half of the UK. And 85% of British people report snacking compared to 10% in France. And in the UK, we have 2.5 to three snacks per day, which translates to six or seven eating events a day, um, and this has massive impacts on our glucose spikes and drops throughout the day causing metabolic chaos. And that's part of what I was thinking as I was, as I was thinking about this is, um, if I'm eating that muffin that you made which r- resembles the sort of typical British composition of a snack, it's not necessarily just that that snack is gonna impact me. It's that my next food choice, because I ate that snack, is going to be different, because I'm on that- I might be on a glucose rollercoaster here. So I might end up making a worse food choice thereafter, which then might impact my- maybe my sleep because I've got a little bit of sugar in me when I'm settling down to go to sleep, and is there the sort of not- downstream domino effect because of that one snack choice?

    3. SB

      So I wouldn't say that you've made a s- a bad- one bad snack choice and that's it. (laughs)

    4. SB

      (laughs) Yeah.

    5. SB

      Your day's over, damn it.

    6. SB

      Yeah.

    7. SB

      You know, your stuffed. I think that you highlight an important point though that what we choose as a meal does have knock-on effects on what might happen later in the day. So for example, if you have a really refined carbohydrate breakfast or snack, then you're more likely to have a blood sugar dip, which we know from our research is more likely to make you, um, more hungry, eat more calories, have lower mood, have lower energy, and be less alert. But I think, you know, snacking can be used to our advantage. Snacking can be used to our advantage because we know it accounts for such a huge proportion of our energy intake, because we know on average that, you know, 70, 75% of the snacks that we do currently eat in the UK and the US are not healthful snacks. And because we know that actually just transitioning from those to healthy snacks can have a big impact. But I think it's really important to be thinking about not just the type of snacks you're having but the time of day that you're having the snacks. And we've published some research recently where we looked in a thousand individuals at people's snacking habits 'cause it's not actually been looked at much. I mean, you'd think everyone snacks. You'd think there'd be loads of science out there about snacking. There's lots of science out there about the different f- you know, foods that we might snack on but not really much looking at snacking habits. And there's a lot of controversy out there about whether we should be grazers, and we are a nation of grazers. You know, we, well, I certainly graze, but many people we know, like you said, you know, 80 to 90% of people do have multiple eating events throughout the day. Are you taking these away from you for self-control?

    8. SB

      I- I am a little bit, yeah.

    9. SB

      (laughs)

    10. SB

      I think, uh, the, the smell of the chocolate and the cookies is testing me.

    11. SB

      (laughs)

    12. SB

      And in general, I'm not trying to be tested. There we go.

    13. SB

      Um, and what we have never really fully understood is, is snacking per se bad? Are you having multiple eating events, so eating six times a day, which we nearly do in the UK and the US, or is it about the type of food we're snacking on? So should we revert back to having the three main meals, the breakfast, the lunch, the dinner?... or is it okay to have multiple meals as long as it's healthy food? So we looked at this in our cohort of 1,000 individuals where we take lots of measures related to what they're eating, when they're eating, how they're eating it, as well as lots of different health outcomes. And what we found was that the frequency of eating within reason was not a problem. So if people were grazing, having multiple eating events, as long as they were eating healthy foods, it didn't matter having multiple eating events. So snacking per se wasn't a problem as long as

  13. 36:55 – 39:05

    Does It Matter How Often We Eat?

    1. SB

      they were healthy foods.

    2. SB

      Okay. 'Cause there's been a long, I guess, raging debate about how many meals-

    3. SB

      Yes.

    4. SB

      ... you should have a day. Some people just eat one meal a day, some people probably eat five or six meals a day. And you're saying it doesn't necessarily matter as long as what you're eating is healthy?

    5. SB

      Yeah. I mean, I will always, as a cautious-

    6. SB

      Yeah.

    7. SB

      ... scientist, caveat it within reason. But our research showed people having six eating events a day, i.e., you know, six different occasions that they're eating food, or three eating events, as long as they were eating or snacking on healthy foods, it did not impact their health outcomes.

    8. SB

      And this is, I guess, controlled for extreme cases where someone's maybe eating at 1:00 AM in the morning or 2:00 AM in the morning? Because-

    9. SB

      Yeah. So we also looked at timing, because I think that's something that we haven't given enough attention to in nutrition science and it's a real exciting new area of research that we're starting to understand, the timing of when we eat is really important. And what we found was, interestingly, 30% of people were snacking after 9:00 at night. And we found that if you snack late at night-

    10. SB

      I feel attacked. (laughs)

    11. SB

      (laughs) And this is a lot, in line with, you know, c- other published research from very tightly controlled clinical trials. We found that if you snack late at night, that that was associated with unfavorable health outcomes. So, uh, worse adiposity, so worse kind of fat around your belly, for example. Um, higher levels of inflammation, worse levels of blood lipids, so, you know, cholesterol, that sort of thing. And we found that this was even if you were snacking on healthy snacks.

    12. SB

      Really?

    13. SB

      And this isn't especially surprising because there's this whole new area in nutrition called chrononutrition, which is all about the timing of eating. And we now are really starting to understand that every cell in our body has its little body clock, has a clock. Every cell has a clock. And that clock is shaped by when we eat as well as the light day cycle. And if we're eating out of sync with those clocks, those millions and trillions of clocks in our body, we know that we process the food slightly differently, we metabolize it slightly differently, and it may have a different impact on our health. And that's what our research showed as well. So eating after nine o'clock isn't great for your health.

  14. 39:05 – 43:45

    Is Eating at Night Bad for You?

    1. SB

    2. SB

      Just to double down on that, I have had a longstanding hypothesis that when I eat later at night, it is making, is, it is basically increasing my belly fat. Now, I, look, I don't have any science to support this, but there's a c- and also, the way that I feel when I wake up is radically different-

    3. SB

      Okay.

    4. SB

      ... if I've eaten close to my sleep time. So I had this weird hypothesis that I'm basically putting food into the machine and then I'm, like, turning the machine off while it's processing, so it's kind of, like, not processed it properly. (laughs)

    5. SB

      Yeah. I mean, that's kind of i- uh, simple terms what's sort of happening.

    6. SB

      Okay.

    7. SB

      You know, w- our body needs to rest overnight, just like our mind does. Our cells, our metabolism needs to rest overnight. And if you're not giving your body, your cells, your metabolism, your gut microbiome, et cetera, that time to rest, things get disturbed a little bit. And what's really interesting is, you said that you feel different-

    8. SB

      Mm-hmm.

    9. SB

      ... the next day if you eat late at night. There's some really fascinating research that came out, uh, about one or two years ago where they looked at giving exactly the same calories and foods over the day within the same time period but in w- i- in one group of individuals, having most of the calories earlier, and in another group, having most of them later in the day. Now, those that were having them later in the day woke up feeling more hungry, which is kind of, like, counterintuitive, isn't it? But it fits in with what you just said. Yet, those people who were eating the calories earlier in the day woke up feeling less hungry. And this is why as well the evidence shows early time-restricted eating, so time-restricted eating where you're eating within a particular time window, those people who are practicing it earlier in the day tend to do better in terms of the health outcomes, whether it's weight, inflammation, cholesterol, than those practicing a later time-restricted eating when they have their last eating event later in the day. And that's 'cause they're eating in, in, in time with their body clocks, with these millions and billions of little cell clocks.

    10. SB

      I have, um, had a weird observation, which is sometimes, v- sort of r- quite rare these days, I have to wake up super early to get on a flight. And it means that I'm disrupting my sleep, maybe getting up at 4:00 or 5:00 in the morning.

    11. SB

      Mm-hmm.

    12. SB

      And for some bizarre reason, w- if I'm d- if I wake up at, say, 4:00 in the morning to go and get a flight, I am starving. But if I woke up at 9:00 that same day, I would not be, I would probably not f- get hungry till about 2:00 PM. And I've never managed to sort of really figure out why disrupting my sleep causes me to be ridiculously hungry, whereas typically, I don't, honestly, eat breakfast, I typically eat about midday or-

    13. SB

      Mm-hmm.

    14. SB

      ... 2:00 PM.

    15. SB

      So I think there's probably a lot going on there. It's getting a little bit outside my area-

    16. SB

      Mm-hmm.

    17. SB

      ... of expertise, but I can certainly comment from work that we've done and that I'm familiar with. So what we know is that sleep duration, sleep efficiency, s- what we also call sleep midpoint, so the midpoint at which you sleep, impacts your hunger levels. We know that your hunger and your fullness hormones change as you sleep. So we know that short sleepers, people who, you know, are getting up too early, so when you're getting up for your flight, then your hunger and fullness hormones might be perturbed. And we know that short sleepers, or if you've had a, a poor night's sleep, you tend to wake up more hungry than if you've had a good night's sleep. This isn't from my own research, I always have to caveat that, but this is what th- some of the research is showing. But that also if you've had a poor night's sleep, you reach...... for less healthy food. And there's a study that was conducted at King's College London by my colleagues called the Slumber Study. Um, and this really n- nicely illustrates how just changing how much you sleep can change your dietary choices. And in the Slumber Study, they asked people who were short sleepers to practice sleep hygiene. They gave them no dietary advice. They just said, "Practice good sleep hygiene," i.e., you know, no screens late at night, no physical activity, caffeine, alcohol, et cetera, late at night, darkened room. And then they just monitored lots of different things in these individuals. And what they found was that those who were able to extend their sleep actually made healthier choices, such that they reduced, without being told to, their intake of free sugar by about 10 grams.

    18. SB

      Oh, really?

    19. SB

      Without being given any advice.

    20. SB

      So they slept better. They ate less sugar. They made the decision to eat-

    21. SB

      Yeah.

    22. SB

      ... less sugar?

    23. SB

      Without being told to.

    24. SB

      Hmm. That correlates.

  15. 43:45 – 48:01

    Sleep Is the Pinnacle

    1. SB

      It's, it's been such a revelation, I think, in my, my life over the last, I'd say, two to three years, is realizing the downstream impact of sleep and a bad night's sleep 'cause it was one of the things that I think growing up, especially as an entrepreneur when you're like consuming a lot of hustlepreneur cult- you know, culture and it's all like sacrifice the sleep, work seven days, that you assume is, um, take it or leave it. Like it, like you, you assume... It's often the first thing you think that you can sacrifice in the pursuit of productivity.

    2. SB

      Sleep.

    3. SB

      Yeah. Well, this is what I, I thought growing up and then, in the last couple of years, yeah.

    4. SB

      But I think, sorry, all, a- I think all 20, 30-year-olds-

    5. SB

      Yeah.

    6. SB

      ... think that.

    7. SB

      Yeah.

    8. SB

      Do you not think?

    9. SB

      I'm, yeah. And anyone that's like r- has, I think, a... probably an involuntary amount of, I say involuntary but I mean just because of the decisions they've made, amount of professional pressure or, like, shift workers or anybody at the, or even parents I guess, um, they probably see sleep as secondary to some other kinda priority in their life. And when I shifted that and I s- I made adjustments to my calendar and my schedule to try and prioritize sleep, the downstream impact of it has been profound in a way that I could never measure or articulate fully, but just everything seems to be better. So like my relationships with my partner, um, my ability to think straight, um, my motivation to go to the gym that day, um, the work that I do, everything.

    10. SB

      Mm-hmm.

    11. SB

      So it's, I've, there's been this big sort of radical adjustment where I now see sleep as actually the f- the, the starting point for all these other choices that I make, good or bad. Um, and that's kind of what your work is highlighting.

    12. SB

      Yeah, I think it's that we have to think of these four pillars together of health. We can't look at diet on its own, can't look at sleep on its own, can't look at stress on its own. We can't look at physical activity on its own. So if we want to improve our health through diet, I think we m- must be looking at our sleep habits, which we can to a certain extent control. Not always. I know some people have to work shifts. Some people don't have a choice. They're woken up by their kids, et cetera. We need to look at our stress. I know that's one of the hardest things to change. Um, we need to look at our physical activity and our diet. And they are all so interconnected.

    13. SB

      And the Predict studies that were done at ZOE found that sleep affected metabolic responses as much as the macronutrient content of the meal. What is, what is that, what is that saying?

    14. SB

      So this is some research that we published where we looked at people when they'd had a good night sleep and we looked at people when they'd had a bad night sleep. And we looked at their post-meal, postprandial glucose response. So that basically means after having your breakfast that's got some carbohydrate in it, how much does your blood glucose increase? We call this the postprandial glucose response because postprandial is Greek for post-meal, and so it's a term we use a lot in the science. And we looked at, um, individuals' post-meal glucose response when they'd had a good night sleep and when they'd had a bad night sleep. And what we found was within the same individuals that had a bad night sleep, their post-meal glucose response, so after breakfast, was a lot higher than if they'd had a good night sleep. So what this shows, I think, quite nicely if we think back to what you said about how you wake up more hungry when you've not had enough sleep, we know that people make poorer dietary choices, for example from the Slumber Study, and then we know that the metabolic responses to those are worse. It just shows how you're kind of creating this perfect storm-

    15. SB

      Hmm.

    16. SB

      ... and how you can't think of it in isolation. 'Cause firstly, you're waking up and you're like, "Bloody hell, I'm hungry." Secondly, it's like, "Ugh, I'm not having that healthy breakfast. I want that pain au chocolat," or, you know, whatever that's, you know, giving you that quick fix. And then you have it and you're gonna have this massive blood sugar peak compared to if you'd had a good night sleep and, and made a healthy choice, were less hungry, et cetera, et cetera. So it's like creating this perfect storm, and it's all started with your sleep.

    17. SB

      Mm-hmm.

    18. SB

      And that's why I don't think we can look at things in isolation, which is how I have spent the previous 20 years of my research, looking at things in isolation. But that's 'cause I've not been... had the luxury of being able to collect the kinda data that we're now collecting.

  16. 48:01 – 50:13

    How to Handle Sleep When You’re a Parent

    1. SB

    2. SB

      I get a lot of messages from parents, so, uh, because I'm not one yet, I don't fully understand what it is to be a parent and the demands of parenthood, so I'm gonna defer to you on this-

    3. SB

      (laughs)

    4. SB

      ... 'cause the parents, they always DM me.

    5. SB

      My children never slept. (laughs)

    6. SB

      They never slept?

    7. SB

      They did obviously, but oh my Lord.

    8. SB

      How did you, how did you survive that as a parent? Like what's the, was there any strategies or tactics you put in place to defend against e- exactly what you just described, the downstream consequences of sleep deprivation?

    9. SB

      No, because the first four years of my children's lives, uh, I was also... I lost my father when my, um, daughter, a few weeks after my daughter was born. Uh, my sister and I became full-time carers for my mother who lived around the corner.Um, I took a career break, looked after my mum with my sister, had two young children. They weren't sleeping, but I had to show up. I had to show up to help my sister look after my mum. It was about survival. I didn't think about what I ate, when I ate. That was irrelevant. (laughs) It was about survival, to be there for my mum, to be there for my kids. And whether it was because the sleep deprivation was also so bad that it was just like driving bad choices, I don't know. But there's points in time in anyone's life that we go through that are about survival, aren't there? And I think everything goes out of the window. And I'm not saying it should, but I think that when you're in the depths of whether it's sleep deprivation because your children keeping you awake or what I was going through, you know, my mother had a degenerative neurological condition, and seeing someone daily deteriorate- deteriorate like that, what you're doing physical activity-wise, well, I didn't have time to do that. What you're eating quite often doesn't become a priority. Now is probably a time it should be even more of a priority because we know that what you eat impacts your mental health. You know, there's great research now showing how important it is. But when you're in that fog of whether it's that you're depressed or you're dealing with, you know, trauma or whatever, I think food is one of the last things that you think about making a priority. And I think it's okay.

    10. SB

      You know, when we talk about

  17. 50:13 – 52:44

    Stress and Its Effect on Eating

    1. SB

      the health situation in the US and the UK, with obesity on the rise and things like that, we, you know, people are now pointing at things like Ozempic as the cure for that.

    2. SB

      Mm-hmm.

    3. SB

      But when you speak about the role there that stress and our lifestyles are having on us, and I was thinking about some of the stats that have emerged around anxiety in young people-

    4. SB

      Mm-hmm.

    5. SB

      ... and them being more, um, and depression rates globally, um, maybe there's something else that we should be thinking about, which is like the mental health mindfulness piece of how that overlays with food choices and... 'Cause, you know, even the food, the ultra-processed unhealthy foods that are being attacked a lot these days, I mean, to some degree, they are a consequence also of demand.

    6. SB

      Oh, absolutely.

    7. SB

      Right? So they wouldn't be making these things if people didn't want them-

    8. SB

      No.

    9. SB

      ... and didn't buy them. So maybe if we focused more on some of the mindfulness, mental health challenges we have in society, people would have more of a, um, a greater ability to make better choices themselves as well. 'Cause I certainly know in my life that if I'm highly stressed or if things are difficult, then my ability to make better food choices is significantly impaired.

    10. SB

      Yeah, absolutely. I mean, you know, again, this is what the research shows. The sleep, the stress, it impacts your ability to make choices about lots of things-

    11. SB

      Mm-hmm.

    12. SB

      ... but equally, your food choices. You know, what you're talking about, I think is so complex. It's where- where's the responsibility for the government? Where's the responsibility for the food industry? Where's the responsibility for us as individuals? Where's the responsibility for schools, for example, or for us as parents educating our children? We need to take into account all of those different, um, areas in order to improve the foods that we're eating. There is a problem that these three dishes, so the chocolate, the biscuits, the crisps, they are more tasty.

    13. SB

      Mm-hmm.

    14. SB

      Or rather, our taste buds, our brains are tricking us into thinking they're more palatable. And that's a problem. Do we say to our children, "You can never, ever have them"? Now, I've certainly never taken that approach. I think it's all about balance and enabling people to make the choices that they make. But I recognize if I'm sitting there in the evening, I'm a bit stressed, I've got a work deadline, I don't want to eat nuts. I want to eat those biscuits or those crisps and I want a glass of wine with it. I know that's not the right decision. I know it's 10 o'clock at night. But in the moment, that's the choice I probably will make (laughs)

  18. 52:44 – 54:21

    Sarah Still Makes Bad Choices

    1. SB

      .

    2. SB

      Do you get frustrated with yourself because you, you know more about nutrition than most people on Planet Earth-

    3. SB

      (laughs)

    4. SB

      ... yet you still find yourself making, at- at times, suboptimal nutritional choices?

    5. SB

      No, I don't, because I think that it's really quite simple when we think about the food that we eat. I think we're making it so complicated, and I think that, do you know what? If we eat a good amount of fruits, vegetables, pulses, if we try not to eat too much heavily processed foods, if we try and get a bit of diversity in our diet, we're doing okay. So what if I go and have, you know, a bar of chocolate? As long as I'm not doing it all day, every day.

    6. SB

      Mm-hmm.

    7. SB

      And I think this kind of health optimization around diet, I think is taking away the pleasure of food. And, you know, I often say if a food is too healthy to be enjoyed, it's just not healthy at all.

    8. SB

      (laughs)

    9. SB

      Food is there to bring us joy. It's to bring us pleasure. It's part of our emotions. It's part of our culture. It's part of, you know, our social connections.

    10. SB

      Mm-hmm.

    11. SB

      And I worry that now there's a certain proportion of society so hyper-focused on that 1% gain in terms of the food that they're eating, that they forget all of that pleasure. So I think I have quite a balanced approach because I know that ultimately if you get the foundations right-

    12. SB

      Hmm.

    13. SB

      ... the rest will follow, but that makes up 95% of what makes a food or a diet, and that's how we need to think about what we eat healthy.

  19. 54:21 – 57:52

    What Does Sarah Think of Diets?

    1. SB

    2. SB

      What do you think of diets?

    3. SB

      Um-

    4. SB

      'Cause there's so many bloody diets, isn't there?

    5. SB

      I think that there's so much nutribollocks out there.

    6. SB

      Nutribollocks?

    7. SB

      There is so much misinformation out there. What you see on social media versus what the evidence shows is like night and day. I mean, seriously. And so when I think about diets, my view on diets-I mean, there are some that there's some good evidence. You know, eat planty- uh, eat 30 plants a week. Yeah, that's great. Um, go on a low calorie diet to lose weight. Great, but how are you gonna maintain that weight? That's a whole other question. Great for losing, not for maintenance. Um, then you've got the alkaline diet. I mean, pfft, I- I don't understand that. Eat alkaline foods, but your stomach is acidic? So n- got no idea how that works. The blood type diet. I don't actually know what half of these diets do, because I do not understand the physiological theory behind them. And so, do you know what though, Steven? I think if it works for you as an individual, fine, do it. But if it works for you at the expense of the pleasure of food, at the expense of enjoying life to the fullness, that's what I think is a shame. Like time-restricted eating, I think there's great evidence around time-restricted eating. Now much of it comes from very tightly metabolically controlled studies, you know, that are done in clinic where people, you know, eat within a five or six-hour window. So they have their first meal at 10:00, their last meal at 4:00 in the evening. Reduces inflammation, reduces body weight, improves blood cholesterol, et cetera, et cetera, et cetera. I don't want to only eat six hours a day. I want to have dinner with my family. I want to have dinner with my friends. I want to go to the pub in the evening. Not every evening. I want to live life. So what can we do that takes that principle of that diet but we still benefit from it? And this is what's great, again, about the research that we're doing at ZOE. We've done this study called the Big IF Study, the Big Intermittent Fasting Study, where 150,000 people sign up and we said, "Look, we want to see if what we find in tightly controlled clinical studies plays out in the real world." 'Cause we always have to think, how does all of this evidence play out in the real world? Does it matter? And we said, "Just limit your eating window, so the time from your first to your last meal, to 10 hours." So that means if you're having your first meal at 10:00, you're having, in the morning, you're having your last meal at 8:00 in the evening.

    8. SB

      Mm-hmm.

    9. SB

      That's correct, isn't it?

    10. SB

      Sure. (laughs)

    11. SB

      (laughs) My perimenopausal brain-

    12. SB

      Yeah, it is. Yeah, yeah, it is.

    13. SB

      ... cannot do maths. Um, that's quite doable for most people.

    14. SB

      Mm-hmm.

    15. SB

      I can have my breakfast at 10:00. I can finish my last meal at 8:00. I mean, yeah, I do like munching on my chocolate late at night. I could probably still live a happy enough life doing that. And we found people could do it. We found as well that people who practiced it, within two weeks, they felt better. They had better energy, better mood. Um, you know, they were feeling a lot better. They also lost weight. Many people wanted to do this 'cause they wanted to lose weight. And we actually see from evidence that people practicing time-restricted eating, even if they're told not to change their calorie intake, just by limiting their eating window, on average reduce their energy intake by about 300 calories on average.

  20. 57:52 – 1:00:44

    Sarah’s Thoughts on Fasting and Calorie Restriction

    1. SB

    2. SB

      There's been a big debate around this, um, conversation around fasting and calorie restriction, and some people say that it's basically the same thing, but- and that you've kind of proven that to some degree.

    3. SB

      So we know that in most instances if you practice time-restricted eating, you unintentionally reduce your energy intake. And the data shows that on average from the studies that are published, it's about 300 calories. Obviously depends on the duration. The reduction in body weight also we know is dependent on the eating window. So the smaller the eating window, the greater the reduction in body weight. But there have been some studies that actually control the amount of calories that people eat, but have some people having it in a bigger eating window, some in a smaller eating window. And what these studies have shown, that if you have the same amount of calories but you change the period in time in which you're eating your food, there is an additional benefit on metabolic health. There is a benefit in terms of blood lipids, in terms of inflammation.

    4. SB

      Okay.

    5. SB

      Independent of calories.

    6. SB

      Of calories. Okay, so-

    7. SB

      Yeah.

    8. SB

      ... time-restricted eating has some benefit independent of calories consumption?

    9. SB

      Yes, but the bulk of the benefit is due to a- a reduction in calories. So there's some benefit independent to calorie restriction, but the bulk of the benefit that we see is due to a subconscious or unintentional reduction in calories. And I think this is when we're thinking about diets, I think we need to think about, how easy is it to implement? Is there any evidence behind it? And 99% there isn't.

    10. SB

      Mm-hmm.

    11. SB

      For the ones that there is evidence, like time-restricted eating, can we do it in a way that still enables us to live our life, that's sustainable? And the sustainable point I think is really important, 'cause there's now some new evidence emerging around consistency.

    12. SB

      Mm-hmm.

    13. SB

      And the importance of consistent eating patterns. And I think this is fascinating. So there's research showing that if one day you're having three meals and then the next day you're having nine meals and the next day you're having six meals and the next day you're having four meals, that troubles your body. It's like, "Whoa, hold on. I'm used to having, you know, four eating events a day." And this is important to bear in mind when we think about snacking. If you're typically a snacker, then fine, carry on snacking as long as it's on healthy food and as long as you have your last snack before 9:00 at night. If you're not a snacker, having me just vouch for the great benefits of snacking, don't start snacking, 'cause you don't want to be inconsistent. And this new evidence emerging around the consistency of eating, and there's some research done actually quite some time ago that started this idea, I think is really fascinating. So try and have a consistent eating pattern. Same applies to sleep. Try and go to bed at the same time, get up at the same time. We've done some work, uh, around social jet lag. Don't know if you've heard of that term?

  21. 1:00:44 – 1:18:46

    What Is Social Jet Lag?

    1. SB

    2. SB

      Uh, I think I've heard of it. What does it mean?

    3. SB

      So social jet lag is where you have an inconsistent sleeping pattern throughout the week. So for example-... for many, maybe 20-year-olds or students, they might go to bed at a sensible time in the week and go partying and crazy at the weekend. Or for someone like myself, I go to bed late at night 'cause I'm late night working, parenting, et cetera, and then at the weekend I catch up. So if you have more than about a one-and-a-half hour, uh, increase or decrease in sleep between your work days or weekend days, et cetera, that's called social jet lag.

    4. SB

      Mm-hmm.

    5. SB

      So it's a bit like jet lag going from one country to the other. And what we know is, and we've published on this from our own Zoe Predict research, people who experience social jet lag, so have this inconsistent sleeping pattern, make poorer dietary choices. They have more inflammation. They have a different gut microbiome composition. Now, it might be because of the dietary choices, but again, it just plays into this whole idea that we're talking about that we can't just think about the food in isolation. We need to think about how we're eating and our lifestyle, et cetera.

    6. SB

      What else is on your nutrabolics list? What things spring to mind that a lot of people believe? I mean, there's a big debate raging at the moment about seed oils because we had a incoming, um, American, I guess he's a politician, um, RFK Jr., say recently, "Seed oils are one of the most unhealthy ingredients that we have in foods and the reason they're in foods is because they're heavily subsidized, they're very cheap, but they are associated with all kinds of very serious illnesses, including body-wide inflammation, which affects all of our health. It's one of the worst things you can eat, and it's almost impossible to avoid. If you eat any processed foods-"

    7. SB

      (laughs) Sorry, I'm having to laugh. This is like nutrabolics beyond nutrabolics, but please carry on.

    8. SB

      (laughs) I mean, that's basically it. Uh, y- he said if you're eating any processed foods, you're gonna be eating seed oils, and he advocates for replacing seed oils with beef tallow, which is, in the UK is referred to as dripping, which is pure beef fat and is a saturated fat. And he's actually selling T-shirts, um, RFK Jr., at the moment that say, "Make frying oil tallow again." So what... So seed oils, uh, what is this weird debate that I've seen r-raging on on my Instagram about seed oils? I've like managed to avoid it, like I've just not paid attention to it. But I see the words seed oils all of a sudden everywhere.

    9. SB

      Okay. So seed oils, I think is at the top of the nutrabolics list. Uh, uh, it blows my mind what you've just read me. It seriously blows my mind. I've done lots of research on seed oils, so I can talk from my own research as well as all the evidence-based that's out there. There is absolutely no evidence that is credible evidence when interpreted in the correct way to show seed oils are harmful.

    10. SB

      What is a seed oil?

    11. SB

      So a seed oil is an oil from a seed.

    12. SB

      Okay.

    13. SB

      So the most common seed oils in the UK is rapeseed oil, which is also known as canola oil in the US and many other countries, followed by sunflower oil. The most common seed oils in the US are soybean oil, followed by rapeseed or canola oil, followed by sunflower seed oil. And there's about three or four arguments that people use to say that seed oils are bad for us. And if you go onto social media, I mean, this is a perfect example of night and day between scientific evidence and what's on social media. If you go on social media, "Seed oils are toxic. Seed oils are gonna give you Alzheimer's. Seed oils are gonna give you cancer. Seed oils are gonna kill you." You look at the evidence, it's totally the reverse. Now, you can have sensible, boring scientists like me say, "Seed oils are really good for you." You could put that as one of your-

    14. SB

      Mm-hmm.

    15. SB

      ... assets or whatever you call it, or adverts for this.

    16. SB

      Mm-hmm.

    17. SB

      So we could say, "Seed oils are really good for you, Steven." Or I could tell you, "Seed oils are toxic. They're gonna kill you. Everyone's trying to kill us with seed oils." What's gonna get more clicks?

    18. SB

      Probably the toxic seed oil narrative.

    19. SB

      Exactly. And so the sensible science, there's no silver bullet. There's no like, you know, crazy inflammatory argument. The sensible science isn't gonna get the clicks. So unfortunately, the voices of reason, and often it comes from boring academics like myself, not saying other academics are boring, but sensible academics like myself that give the, you know, the balance, we, we don't get a voice. We're not being heard, which is one of the reasons that, you know, I wanted to come on this show because of the misinformation and we have to get the voice of reason out there. We have to get the voice of reason so things like that to do with seed oils are not what's dominating the headlines. So what people say in terms of seed oils is firstly, "Our intake of seed oils has increased a hundredfold the last 20, 30, 40, 50 years. And with that increase in seed oil intake, so has cancer increased, so has cardiovascular disease increased, so has obesity increased, so has Alzheimer's, et cetera, et cetera. So it must be to do with the seed oils." Well, what else has changed in that 50 years? We're more sedentary. We eat loads of these other, you know, heavily processed foods that got all of these other ingredients in, you know, the sugar, the this, the that. So much else has changed. You know, you can't put it all down to the fact that at that point in time, seed oils were also changing. We also know that about 60% of the seed oil that we eat is actually in these heavily processed, unhealthy foods. So it's the first argument they say, and you see these beautiful figures that they put out where you see on one axis the intake of seed oil. You see on the other axis, um, you know, s- o- over time, you'll see, uh, for example, like rates of cancer and you see rates of cancer or rates of cardiovascular disease going up linearly with the intake of seed oil. But we have to think what else has changed in that time. The other arguments that they use are theoretical arguments based on biochemical pathways. And I spend...... an hour teaching this to our undergraduates, and I'm not gonna bore you with that biochemical part. (laughs)

    20. SB

      (laughs)

    21. SB

      But they talk about the ratio of, um, a particular fatty acid, which is omega-6, which is found in high levels in seed oils, and omega-3, which is another fatty acid, and they talk about how having lots of seed oils changes this ratio, makes, uh, this pro-inflammatory state because it increases a particular downstream chemicals, et cetera, et cetera. What we know from kind of theoretical biochemical pathways and enzymes, et cetera, doesn't actually play out in humans. We're so clever. We have all of these mechanisms in place to control inflammation, to control oxidative stress, to control downstream impacts of foods. And so, this argument that is also used to say that omega-6 fatty acids, so the main fat that's found in many of these seed oils, is pro-inflammatory, is not supported by any evidence. It's not supported by tightly controlled clinical trials. If anything, it's shown to be anti-inflammatory, that levels of inf- inflammatory, um, circulating molecul- molecules actually reduce. And yet, they use this kind of theoretical argument or what they've seen in a Petri dish, for example, or in a test tube.

    22. SB

      So where does this narrative come from? Where, where did it originate from, that seed oils were, were toxic? Was it just one of those things that just snowballed?

    23. SB

      I think it's one of those things that snowballed, and I think it does fit in with the whole, uh, argument that people are using against all the processed food. It does fit in with other, other narratives that are going on. I think some people can be very clever in cherry-picking research.

    24. SB

      Mm-hmm.

    25. SB

      So there's a su- study called the Sydney Heart Study, and in this study, this was done in the '70s, and this is a study that's used often to advocate for the toxic effects of seed oils. And in this study, uh, males that had had a heart event or a heart attack of sorts, uh, were, uh, randomly allocated to either increase, um, their omega-6, so this particular type of fatty acid that we... is in seed oils, um, in their diet by having lots of seed oil.

    26. SB

      Mm-hmm.

    27. SB

      Or they were asked to just follow their normal diet, which is quite high in saturated fat. And what they found is those that increased their seed oil intake went on to have worse health outcomes. Now, the problem with that is, is that in those days, the majority of seed oils underwent an industrial process called partial hydrogenation, and partial hydrogenation produces a very harmful fat called trans fats. You might have heard of trans fats.

    28. SB

      I've heard, heard the word, yeah.

    29. SB

      And so they were eating this seed oil in the form of a margarine or fat spread that had undergone partial hydrogenation and therefore was full of trans fats. Trans fats increase cholesterol. Trans fats increase inflammation. Trans fats are bad for us. That's why they are not in our food supply anymore.

    30. SB

      Mm-hmm.

  22. 1:18:46 – 1:21:10

    The Lies About Dairy

    1. SB

      There's a lot of nutribolics around dairy, right?

    2. SB

      Yep.

    3. SB

      Um, I think the prevailing nutribolics is that dairy is bad for you.

    4. SB

      Yep. So there's not- lots of nutribolics around dairy and it's related to the nutribolics also around saturated fat. So as a whole, we know saturated fat is bad for us. Dairy contributes to most of the saturated fat intake in the UK.... so therefore, we could say all dairy is bad for us. But no, dairy is a diverse food group. You've got cheese, you've got yogurt, you've got butter, you've got milk. And how they impact our health is vastly different depending on whether it's a liquid, a solid, it's fermented, it's non-fermented, et cetera, et cetera. And grouping them all together is as ridiculous as grouping all these snacks together in terms of the health effects. And what we now know is that some dairy is actually good for us. So some dairy-

    5. SB

      Hmm.

    6. SB

      ... like cheese, like yogurt, and I don't mean this really kind of heavily sweetened sugary yogurt, I mean, like, your Greek yogurts, your kefirs, those sorts of things, your plain yogurts, they've undergone a process called fermentation, and that changes the food matrix. So again, we're coming back to that whole importance of the structure of the food. And by changing the food matrix, changes how our body handles it, how our bodies... How... The health effect of that cheese. We don't fully understand how.

Episode duration: 2:11:28

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