The TRUTH about intermittent fasting

24:51So I think you've got to realize that you want to do this as a long-term goal. And we know that if you can do things five days out of seven, you're doing pretty well. But occasionally, you know, I might be in France and there's an incredible breakfast buffet and I'm saying, oh, really, am I going to miss all that? I've paid for it. It's free. And so sometimes I just do it. And, you know, life is too short not to take rare opportunities as well. We ask ourselves, is it window worthy? If it's window worthy, the window gets longer. That's what we say. That's brilliant. So that means this is window worthy.

25:25Is this window worthy? It means this is so appealing. Yes, it is. I am going to eat outside. I love that. That croissant looks so good. Oh, that's window worthy. It's my one croissant of the year. I'm going to have it here. That's right. So look, I think there's a brilliant discussion about where we are. Gin, I'd like maybe to start almost a bit with me. So I went through this study. I was like, I feel like, well, everybody's been asked to do this study. I should try it as well. And you talked about how there's like an average. And then there's always like all the individual responses. So I did this.

25:55I followed it really properly. And I found it really hard. And my mood got worse. It did not get better. Were you hangry? I was not even sure that hangry was quite like, I think genuinely it felt like my mood was worse. So different from being angry, but actually like, I think I was, I felt like less happy. Like it felt like, um, like a real struggle. Yeah. And so I'd love to talk about the practical advice in general, but also maybe talking through the idea that it's not always just super, because I've heard other people say, oh, it's so easy. I just started doing it tomorrow and it was fine.

26:30And in my own experience of this has been, no, I found it quite easy. to do like the fasted exercise, because that's just like sort of ad hoc in just the way that you described interesting, which I was terrified of. I was convinced I would fall over and drop something heavy, you know, on my other toe because I hadn't eaten food. And it turns out that you can, to me, really remarkable. I think for anyone who's never done this, it's like, it turns out that you can sort of do all this exercise, even if it was something hard, like something heavier lifting or going for a run or whatever. And you'd be like, oh, I did that without any breakfast, and it felt exactly the same.

27:05So that has been sort of eye-opening. But actually managing this sort of time-restricted eating for long enough to start to come out, truthfully, I couldn't do. You didn't get there. And the day that it was over, because you described that many people in the study decided to keep going, I was like, so happy to not have to do this. But point out that you and I are quite different, right? Yes. So when we go out, you know, you're always thinking about your next meal, right? You've got this, you say, where are my snacks? You know, we can't have a sit-down chat without something to nibble on. I'm feeling judged now, Tim.

27:38Well, you know, you appear to be naturally a grazer. Correct. And I think I'm naturally this is how I am. And I'm a gorger, right? I'll sit down and have a really big, and I might eat more at my main meals. So it could be the way he was brought up. It could be genetic. It could be any number of things. But there are clearly differences between people. And that's maybe why in the Big If study, a lot of people dropped out or didn't like the idea of it, who might have been a bit like Jonathan. The way I'm hearing this, you're just pretty much feeding, grazing throughout the day. And when your blood sugar dips, you feed yourself something else, right?

28:12Is that kind of what? So I've definitely changed what I eat a great deal. So I would say that I eat a very good Zoe diet in terms of the food that I'm eating. But I'm naturally someone who continues to snack between meals. I'm eating things differently. And I absolutely love eating. eating dark chocolate on the sofa in front of the TV when I finally stop work, which can be quite late in the evening. And I think this is great. Let's talk with me practically. How would you get someone like me to get started in this? Because I think lots of people are listening to this saying, okay, that sounds interesting.

28:46But we've also described, yeah, how do you get started? And also to explain more practically, what does that really mean? What are you allowed to do outside? So maybe take us through that, Jim, but then maybe with me also in mind, what I might be able to do better if I try this again. Well, the key is becoming metabolically flexible. And that is when you are able to wake up, delay, and you're fine, and your body just uses the fuel that's already on hand. You know, we've got glycogen stored in our liver and in our muscles. We have lots of stored fat on our bodies. Even if we're lean, you still have fat stored on your body.

29:16And the key is, is your body going to tap into that or is your body telling you, all right, go ahead and send something down? And you're used to feeding yourself whenever you're hungry. And there's nothing wrong with that. It works well for you. You're a healthy weight. You're eating high-quality foods. But if you want to extend that period of time since you get some of those lowered inflammation, things like that, that Tim was talking about, it's just a matter of just kind of nudging it in a little bit. You know, I would stop a little earlier at night, nudge that breakfast a little later. You know, my husband never needed to lose weight.

29:50He starts right around when you do. He has his first meal of the day around 11. and we're usually done by about 7 p.m. at night, like I said. So he does all of his eating between like 11 and 7. Never needed to lose weight. He just found, you know, well, you know, I'm sold on the health benefits. He'd watched me do it. You know, I lost 80 pounds with intermittent fasting. I've been doing it for about 10 years now, and I've kept off the weight. But he said, yeah, I'm sold on the health benefits. I would like to have some time when I'm fasting. So he just skips the breakfast and goes about his day.

30:21The thing is, is that there is that adjustment period. And you were just right in the trenches of that. You know, I first heard about intermittent fasting in around 2009. And I dabbled in it for years and continued to get heavier and heavier because I would do it for a couple days. Then I would take a few days off. My body never became metabolically flexible. I lived in the hard part. But you really have to get past that hard part where your body learns to flip that metabolic switch. That's terminology I got from Dr. Mark Mattson. Have you read some of his work? He was a Johns Hopkins researcher, and he wrote a paper called Flipping the Metabolic Switch, where he really talked about what has to go on in your body to really become adapted to intermittent fasting.

31:04And I love that terminology because that's really, boom, that's what happens. You're not metabolically flexible when you begin, and the more you've been a grazer, the longer you've stretched your eating, the less metabolically flexible you probably are. And when you're saying that, you're meaning that instead of relying on there being sort of energy that's coming from food that you've recently eaten, it's suddenly I can actually tap into all these energy stores in my body that haven't just literally come from something I've eaten in the last couple of hours. Because think about, you know, how we're designed.

31:35If you go back, you know, thousands of years, there wasn't a snack on every corner. People had to be metabolically flexible. You had to be able to have sustained energy to go hunting or gathering. You had to be able to make it. Your body had to be able to say, all right, no fuel's coming in. I can access the fuel I've already got. Can you imagine, you know, if people were like, well, I can't go hunting because I'm too tired. I can see you're in big trouble. It's like there's not enough food to go out and get any would be a big problem. I can see that. Yeah, you wouldn't live long. Tim's laughing.

32:10I lived with this hunter-gatherers for a week, you know, 10 years ago. And, yeah, they don't eat anything before 11 o 'clock in the morning. They just do it. Nobody told them to do that. No, and they don't really eat after 7 p.m. These are our ancestors, you know, from East Africa. So I think it makes sense that our bodies were adapted for that and that your pattern of eating has adapted the fact we're surrounded by food all the time and that it's not actually a necessity of your body. Right. So, Jin, talk me through. Imagine, start at the beginning, like day one, And I know that this is something you cover in your latest book.

32:48So someone's listening to this and they're like, this sounds interesting, but I don't actually really have any understanding of what I'm supposed to do. What do you need to do? Well, the book is called 28 Day Fast Start Day by Day. And it's for people who really need like, what do I do? It's day one. How do I start? And you get to pick how to start. Everyone isn't starting at the same place. You start at the beginning. You take a quiz and you figure out, am I a rip off the Band-Aid person or do I need to ease in or am I somewhere in the middle? And then every day I tell you exactly what your eating window is going to be for that day.

33:18You're starting off with a longer eating window at the beginning, week one, and then you gradually shorten that. Depending on which plan you follow, everyone is shortening it by the end. With the goal of you're teaching your body to become metabolically flexible, you're adapting, you're pushing through those hard parts. So there's a sort of step-by-step reduction you're describing. So you don't suddenly jump from like I eat for 14 hours and suddenly jump to eating for eight hours the next day. No. What does eating mean? Because I think we sort of referenced the side, hey, you know, if you go and have a beer, that actually counts as eating.

33:49But could you help people understand what is eating and what isn't? So when you're fasting, you are having black coffee, nothing added to it. We're having plain water, no flavors, water enhancers or anything like that. And we're having plain tea, regular tea, not an Earl Grey because Earl Grey has got flavors added. It's got the bergamot, wakes up people's appetite. So we're sticking to plain water, black coffee, plain actual tea during the fast. No herbal teas. Well, here's the thing about herbal tea. We want to stick to something that has a bitter flavor profile. We're trying to prevent an insulin response.

34:24And the cephalic phase insulin response can happen if your brain perceives that something's coming in that's got a hint of sweetness. So if you're having like a raspberry or apple cinnamon. There's definitely no sweetener or anything like that. Even though it doesn't have calories in it. Right. You're saying this is your practical experience. It's a practical experience for people that have struggled with intermittent fasting. And then they're like, well, you know, I saw a video that said I could put a little splash of almond milk and it didn't matter. Or I could have, you know, zero calorie sweeteners in there.

34:56Or I was drinking a lot of these herbal teas. And they found fasting to be very, very difficult. Black coffee, nothing added. Plain tea, plain water. You know, just that little bit of lemon in there. It's going to make it harder. So when you were doing the fasting part of it, were you drinking just black coffee, just plain water? Earl Grey tea, probably. Earl Grey tea. Earl Grey tea. But nothing else. I thought I was doing very well. Earl Grey has the bergamot oil in there, and it's got that citrus flavor. You just made it harder for me now, though. I can't even have that. No, it's going to be so much easier.

35:31Here's just an example from my life, and it's truly just an anecdotal, but this is just an example of that. So I was at a restaurant with my son and about to eat, but I hadn't eaten yet. So I was about to open my eating window, and I'm just fine. When I'm fasting, I'm just fine. So I order club soda with lime, start drinking my club soda with lime. Suddenly, I could like have eaten my arm off. I was like, I have got to eat now. I am starving. That little bit of lime in that club soda. You know, I know what it feels like to fast clean because I've been doing it for so many years. But just that little thing that you might think, how could that possibly make a difference?

36:07It absolutely does. And is it just in your mouth or do you have to swallow it? The cephalic phase insulin response, these were rodent studies that they did. But it was fascinating. They painted the oral cavity of these little rodents with artificial sweeteners. That's like their mouth. There's pain of their mouth with it. They didn't even swallow it. They just tasted it. And they had a cephalic phase insulin response. That means their little rat pancreas released some insulin in response to that. So then in part two of the study, which was not as humane, they snipped the nerves from the tongue to the brain, repeated it.

36:39The rats could no longer taste it because those nerves were severed. They did not have the cephalic phase insulin response. So it was the taste that made the difference. And what does insulin do? Insulin lowers your blood sugar. Why is your body releasing insulin in response to these sweet flavors or these food flavors? Because our brains know that sweetness is coming from honey or fruit or whatever. Our body doesn't understand. So they think you're going to eat a raspberry, even if it's just raspberry tea that doesn't have any calories. Exactly. So your brain says, we know fruit. Fruit has a sugar load coming in.

37:08We're going to need a little insulin to handle that. And so then your pancreas releases the insulin, only you've had like zero calories. So then it actually could lower your blood sugar and make you shaky and you feel worse than if you hadn't had it. And your body might think you're hungry then. Then you're starving because your blood sugar has crashed. And, you know, if you're wearing a CGM, you could actually see it as a blood sugar crash after having that tefalic phase insulin response. Coming back to something like thinking about this day by day. Yeah. This really clean fast outside of the hours I'm deciding to eat.

37:39What else do you need to know in order to make this transition? Well, that's it. You just fast clean and you just work your way in to what feels good to you. We don't expect weight loss for the first month because your body is learning how to do something new. Sometimes people find, because you're not metabolically flexible yet, you're not fat adapted, we call it. You're not really tapping into your fat stores very well because your body hadn't had to do that for a long time. If you've been eating like most people eat, you actually might overeat in your eating window at first because you're not well-fueled during the fast.

38:10Your body can't really tap into your stored fat. So you open your window and you're like, I'm starving. And then you just overeat. That goes away once your body flips that metabolic switch. So don't get anxious about that if you feel like you're overeating. This is never going to work. I open my window and I'm eating too much. Eventually that settles down. I definitely feel like, I don't know if that's common, I feel like I had some anxiety about Tim's laughing, but I had some anxiety as it's coming towards the end of the window. Right. That like, I might not have eaten enough food. You might not survive the night.

38:39Not that I might not survive, but that like I might be hungry and it's going to like affect how I feel. Well, here's the funny thing about that. Because normally I'm like, I don't worry about that. If I still want to eat more food, I can get more food, right? You don't have to eat for future hunger. That's the beauty of it. You just close your window. You're not eating for future hunger. You go to bed. Actually eating later into the night is going to make you hungrier earlier than if you had stopped sooner. So like I better eat a lot because tomorrow morning I'm going to be fasting. Actually, we'll make it harder for you tomorrow morning than if you haven't.

39:10Quite counterintuitive. Yes. And how long would it take you to get Jonathan into shape then? Well, if he's going to fast clean now and not have the Earl Grey, I think you're going to be amazed. So how long do you think it would take me to switch from saying this is really hard to saying I'm starting to get all those benefits of mood and energy? Two weeks. Yes. Like I'm having hot water in a mug right now. Just plain hot water. Just wake up and have that. Or you used to a little caffeine in the morning. You could have some black tea. I stick to my black coffee. I bet you could do it right away.

39:41Well, I think you're challenging me. I am. I am going. I'm willing to give it two weeks. Okay. I can't do a whole month. I'm willing to give it another two weeks. Give it two weeks. With the clean fast. Just try to wait till 11. See if you can wait till 11. Report back. And imagine, you know, your body is doing all these great things. So that really helps. Instead of thinking, can I eat yet? Can I eat yet? You know, checking your watch. Think, I am giving my body some time to have some digestive rest. My gut microbes are having some downtime. I've always found when I did more extended fast that the busier I was, the easier it is.

40:12Absolutely. So I would never suggest to anyone start at a weekend. Right. Because that's the worst time. Yeah. Yeah, you're staying busy. Is that your experience? Oh, absolutely. Right. If you have time to sit around and mope about it, that's when you're like, well, I've got nothing to do. I sure would like to have a muffin. Right. But if you're busy, you don't even think about it. Yeah. And what about the length of time, Tim? What's the evidence there? Because I know this is an area that's still up for a lot of discussion. But for example, I'm probably eating 14 hours a day. Not every day, but like there's definitely a whole bunch of days when I'm eating 14 hours.

40:45I'm understanding from quite a few scientists I've been talking to reset is probably not ideal. But on the other hand, I think you're definitely not sitting here saying people should eat all their food in four hours. We don't have big enough studies in a wide enough group of people and not enough, particularly women in our studies, although, you know, we were lucky in the majority were women in the big if study. But it looks like the sweet spot for when the results start sort of turning significant is around at this 10 hour eating window. So if you can get to 10 hours, that's fine. There's some evidence that maybe 11, you know, could be okay.

41:20And there's probably differences between people. So we're talking averages here, which might vary at different ages and between men and women. We don't really know yet those differences. So at the moment, I think it's do something that's sustainable. So if you can have a 10 hour eating window that appears to be sustainable for years, because it's what our ancestors did. That's pretty easy, but for some people, they might want to get it down to eight hours. Others might be okay at 11. And to flip it on the other side, my sense from you and Sarah and others is like over 12, you seem to be saying like, I'm really skeptical that that is a good thing for you.

42:00Correct. I think that's right. All the data suggests that there is a linear relationship between how long you can do it for and in terms of the biological benefits. But at the same time, it gets harder to do it for most people. So it's this trade-off of where these two lines go. Does that mean you're pushing that if somebody could eat all their food in one hour, that would be better? No, we don't recommend that day to day. We know that people who only have one meal a day struggle to get enough calories or vitamins or nutrients. And so for the vast majority of people, that is harmful. And so many athletes and things have tried that and it fails miserably.

42:41We do not want to have a really short, short, short, tight eating window. Now, how you define really short and tight depends on the person. You know, I'm someone, I've been doing this for a lot of years. I'm about a five-hour eating window. That is my sweet spot. That works really well for me. I'm able to nourish my body well. I'm able to maintain my weight. So I think really the key is what are someone's goals? You are not attempting to lose weight. You do not need to lose weight. It would not be good for you to lose weight. But if someone had a great deal of fat to lose, they have to give their body time to burn more fat.

43:12So that's when you might find shorter eating window. But still, no, one-hour eating window every day is definitely not something we recommend. So a 10-hour eating window. And then the question is, should you do that early or late? And the evidence says, well, if you find it easy, do it early. But if, like me, it doesn't fit in with your life, et cetera, and you go out a lot in the evenings and you socialize, then it's better not to try and force it. On average, it might be better to have it start early, but actually in reality, if it's the thing that's most important, it's a bit like we say with everything else, it's like what's sustainable is what's healthy.

43:45And that's why two thirds of people in the Big If study picked the late eating window as easier for them to get on with their life. So I think there's always this difference between the theory, what happens you can do to mice or to paid students in a laboratory, and what happens in the real world. And this is what we're discovering. What are people really going to do? Because that's what matters. If you can't do it and you don't enjoy doing it, you're not going to do it. Exactly. And if you went on holiday to Italy or Spain, you wouldn't be able to eat in the evenings. You wouldn't find a restaurant.

44:19So I think there has to be some flexibility built in related to culture and work practices and where you are in the world, your family and all these other considerations. But I think what we're giving people is a blueprint here that they can adapt this science to their own lifestyle. Can I come back to one of the questions at the very beginning? Because we had this from a number of listeners, which basically said, you know, if I follow this really strictly, can I eat what I want? Can I eat whatever I want? The answer to that is yes, but also no, right? And it's really on the emphasis. You know, if you think about eat whatever you want, that implies that you're going to go crazy and you're just eating everything.

44:59That's not going to work very well for health. It's not going to work very well if you want to lose weight. But you can eat whatever you want, meaning if you're someone who does better on a more whole food, plant-based approach, you can absolutely do that with intermittent fasting. If you're someone who is right now eating the standard American diet and you haven't changed your diet yet, you can implement intermittent fasting, continuing to eat what you're eating right now, knowing that you're making positive benefits. But then a funny thing is going to happen. Most people who start off eating whatever they want, standard American diet, over time lose their taste for that.

45:36They find that, hmm, what I want is different now. Mine certainly did. When I started in 2014, I was eating the standard American diet. I was obese. I was 80 pounds heavier than I am now. I liked fast food. I liked takeout. Now, I don't eat that way. And it's happened naturally. My body has directed me towards more nutritious food. And so you feel that the long periods of not eating have helped you, as it were, to sort of fight back against them, maybe this ultra-processed food and these other things? Is that what you're sort of suggesting? It's a very common thing we see in our intermittent fasting community.

46:10People suddenly are like, huh, I tried my favorite coffee creamer that I used to enjoy. And now, you know, they're drinking their coffee black during the fast, but they had it during their eating window. And they're like, and it tasted like poison. I no longer like it. We lose our taste for things that we used to enjoy. It's pretty much something that happens almost universally over time. Yeah. I think the question goes to, well, do I not have to worry about calories? I think is the sort of thing, because if you're doing this intermittent fasting, does that mean you're off the hook and you can have unlimited calories?

46:40No. No is the answer. You know, donuts are not the answer. Right. Or the reward for this. But it just means that you still have to eat the same way. It's a healthy plant-based way. The don't count calories because we know long term that's not a good solution, but still worry about food quality. It's a complement to quality, but it doesn't suddenly overrule that. Absolutely not. And as Jim's saying, by giving yourself a bit of a break, you perhaps are going to feel more the quality of your food than you've done before. By having black teas and black coffees, you are perhaps introducing more bitterness into your flavor systems, in your brain and you will naturally just slightly be lowering the need for sugar and things like that.

47:30You're exactly right. I really think that having the black coffee, the plain tea, I mean, our taste buds change over time. They regenerate. You got new taste buds in a few weeks. And so if you train your palate to enjoy the black coffee, enjoy the black tea, suddenly you're like, oh, a Brussels sprout, that's delicious. Because you tolerate those bitter flavor profiles from the vegetables more. One of our previous guests that we had recently, Professor Karen Esser, who's focused on circadian rhythm, particularly within muscles, was concerned that for people over 70, they might not be able to eat enough or get enough protein within a time-restricted period, despite actually being quite positive about this sort of more broadly.

48:14I was really interested in your thought and then also, Jin, your sort of practical experience across. But for this group, you might be saying, hey, this is a general rule, but actually here are categories where you would think differently. I think it's something you think about, but for the majority of people, it's not a problem. I think if you are both trying to lose weight and you are exercising a lot, then having too dramatic a change could be problematic in that small group. But I think what we're talking about here, these rather modest changes, you know, changing your eating window from, say, 12 hours to 10 hours, is not really going to affect anybody.

48:56I think only if you're going down dramatically would that have an effect because you wouldn't be able to get enough calories or protein during the day in that eating time. And that's perhaps what she was referring to is these more extremes of these fasting periods. But for what we're talking about here, which is very modest changes that would last years, people would be getting all the nutrition, in my opinion, that they need. And one thing we find over and over again in the intermittent fasting community is that we become so much better at listening to our bodies. We have built-in hunger and satiety signals that drive our eating.

49:33And protein is an example. I eat a lot of plants these days. And, but every now and then I'm like, I really need some meat today. My body lets me know. If I eat too much meat, I start to feel sluggish. So I don't worry about, well, am I getting enough protein? Because I really feel like my body lets me know. You know, people are not really satisfied until they've had enough. And your body will tell you. I think that that's absolutely right. As long as we're sensible about it, as long as we have a whole variety of foods, that we're not excluding large areas of foods, and we're not trying to go into a tiny window.

50:07and at the same time lose a lot of weight, then I don't see this as a problem. We'll have plenty of protein in plants and other things as long as we get that variety. And, you know, we're not so limited that we haven't got enough time to eat all we need. And I wanted to add, you know, working your muscle is important as you get older. So I've become a lot more intentional when it comes to working my muscles because use it or lose it, right? Eat protein, eat sufficiently within your window, but you also have to be doing activity. I'm an elderly person now. Are you elderly? Very elderly, yes. It definitely does not look elderly.

50:41But, you know, in my 60s, and, you know, I've practiced this for years and certainly only seen benefits. So I'm not seeing my muscles fading away. So it sounds like you're saying be pragmatic about particular cases, particularly where people may be trying to lose weight or you see that they're losing weight or they're sick. Or they're sick, right? I can't get that. Yeah, obviously, there's common sense. But in general, again, because you're not talking about very narrow windows where it's sort of impossible to eat, this is not very concerned about. You nourish your body well. My book that I wrote in 2020 is called Fast Feast Repeat.

51:13It's not fast, eat a little diet meal repeat. You know, we want to nourish our body well. I think that's a beautiful place to stop this time. Let me try and summarize, and I know you're both going to keep me honest. We started by saying sort of what is intermittent fasting? And today in 2024, that's mainly this idea, this other term of sort of time-restricted eating, it's saying, I'm only going to eat for a certain number of hours each day. And in general, it's going to be on sort of the same cycle each day. And then there's a discussion about how long, which could be, you know, as long as maybe 12 hours, at some cases down to, you know, six to eight or something at the other end.

51:53And Tim, I think you said, like, there's really nothing harmful for most people and great potential for benefits. So it's something that we shouldn't be scared of and equally well, it's not going to solve everything either. But it's something that is quite exciting. You then share the results from this brand new study, the Big If study that we did at Zoe with 148 ,000 people who participated, which is a 10 hour eating window, which from Jin's perspective is still a relatively wide window, which means like 14 hours of not eating. It was for two weeks. And what you saw was there was a small amount of weight loss, which is like two pounds, 1.1 kilogram, which you said is a minor change.

52:33But the thing that was sort of more exciting is you saw these improvements in energy and mood and a fall and hunger in just two weeks on this very large sample of sort of real life people. And that interestingly, it worked particularly well when they were consistent in their patterns. People were more inconsistent, actually ended up more hungry or less energy. And then there was people like me who just were like, this is miserable. And that practically speaking, again, you saw that people tend, who got this to work and stick, tended actually to be having their eating later in the day, which is a bit at odds with some of the guidance about health.

53:03The reason why we believe this might be working is we think that this is lowering inflammation in the body because it's sort of not being forced to sort of work at times when sort of we're evolved, you know, not to have to deal with all this stress from food, and that this small change in inflammation over time can really add up. So it can really affect your health from your immune system to then affecting like every part of your body. So it really could add up and improve, you know, how long you have quality of life. Jin, I think you talked about then practically what does it mean? Critically, if you think about it, like you need to accept there's a period of transition.

53:39So you can't just switch tomorrow and find it easy. So I was probably expecting something too easy because you need to move to what you described as metabolically flexible, which means being able to just do your normal stuff off your reserves rather than off food, that in general, people find it easier to continue their fast in the morning. So if you're trying this transition, it's a lot easier to say, instead of eating breakfast at 7.30, I'm just going to shift it later. Secondly, you need to have, be very strict about what you're doing outside of the eating window. So clean fast is what you said.

54:10So I can have black coffee, plain tea, but I'm not even allowed like my Earl Grey or my herbal tea or any of these sorts of things. Keep all that in your eating window. You could have hot water, you can have coffee, but that's basically it. Not to worry too much if you're overeating during the fasting period at first. It will balance out. And then also to recognize, though, it's not like this magic bullet. You can't eat unlimited calories during the eating window and expect to magically not put on weight. You have to continue to think about the quality of food, right? Like, ultimately, this is not going to outweigh the fact that you need to eat food that is really healthy for you rather than, oh, it's fine.

54:49I can go and eat my donuts because I'm only eating for four hours a day. And then maybe to finish, we talked about sort of the eating window. And I think my takeaway, and Tim, correct me if I feel this wrong, is like over 12 hours is not good, which is actually similar to the advice that Sachin Panda gave on the podcast recently. Really short is also not good. So you're not, neither of you are believers on like one meal a day is the secret to health. Now, can I pop in there about the idea of one meal a day? Yeah. I loosely think of myself as one meal a day, but over five hours. Think about it as a multi-course meal spread out over like, I have an appetizer and maybe a salad course.

55:26It's a feast. It's a feast, right? But we're not talking about one hour. No, no. Got it. And therefore, I think, Tim, you said this, your sense of the moment is a sweet spot from like both health and sustainability is about 10 hours. But still, the date is quite early. And so. And it might vary between people. So this is just very much. average and we don't yet know for different ages and men and women and people with different conditions. But that's the current state of the evidence we have. And I can just tell you anecdotally, it absolutely varies from person to person. We are each a study of one when it comes to figuring out what works best for you.

56:02There is no like, here's how everyone should do it for intermittent fasting. Yeah. So that's why, you know, don't beat yourself up if you can't get exactly that. If you need an extra hour and that works for you, that's absolutely fine. I think it's all about listening to your body. And this is really what we're trying to get people to do is not don't listen to dogma, listen to your body. Love it. I think that's a wonderful place to stop. Thank you both very, very much. I hope you learned something today and enjoyed the episode. If you listen to the show regularly, you probably already believe that you can transform your health by changing what you eat.

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