Feel Better, Live More with Dr Rangan Chatterjee - BITESIZE | Why Intermittent Fasting Works | Dr Jason Fung #373

Starting point is 00:00:00 Today's Bite Size episode is brought to you by AG1, a science-driven daily health drink with over 70 essential nutrients to support your overall health. It includes vitamin C and zinc, which helps support a healthy immune system, something that is really important at this time of year. It also contains prebiotics and digestive enzymes that help support your gut health. It's really tasty and has been in my own life for over five years. Until the end of January, AG1 are giving a limited time offer. Usually they offer my listeners a one-year supply of vitamin D and K2 and five free travel packs with their first order. But until the end of January, they are doubling the five free travel packs to

Starting point is 00:00:51 10. And these packs are perfect for keeping in your backpack, office, or car. If you want to take advantage of this limited time offer, all you have to do is go to drinkag1.com forward slash live more. Welcome to Feel Better Live More Bite Size, your weekly dose of positivity and optimism to get you ready for the weekend. Today's clip is from episode 285 of the podcast with Dr. Jason Fung, one of the world's foremost experts on intermittent fasting. Dr. Fung has helped countless people all over the world improve their health and well-being. And in this clip, he shares some easy ways to practice intermittent fasting and reveals why the rules aren't as strict as you think. Please note, the advice in this episode may not be suitable if you are suffering from

Starting point is 00:01:51 or recovering from an eating disorder. It's funny how culture has changed so much just in the last 30, 40, 50 years where this idea of eating all the time has become just so prevalent. And Professor Sachin Pandey from the Salk Institute, he was sharing information with me from his app that people are tracking how often they're eating for. And he said 50% of non-shift workers in the US are eating pretty much over a 15-hour period each day. Now, technically it was 14 hours, 45 minutes, but basically 50% are eating over 15 hours. And he said under 10% of people that they were tracking were eating in under a 12-hour window. Now, if we compare that to 100 years ago, this is so abnormal, isn't it? This is so not how we have lived for most of our revolution.

Starting point is 00:02:53 And I guess the question then is, why is this problematic? And when you use the term fasting, what do you mean by it? Yeah. And it's really just fasting is just any period of time that you're not eating. I mean, if you think about the 14 hours, 45 minutes, if you wake up at 8am and you start eating immediately, you're eating until 10.45pm, right? That's basically your entire waking day. And that's the average. But the reason it's so bad is that your body really exists in one of two states. It's either in the fed state, which is you eating, insulin is high, which is telling your body, please store some of these calories that are coming into your body because you're going to need them for when you're not eating. Or it's in the fasted state, which is insulin is low, you're not eating, and your body says, hey, I need calories, please take them from

Starting point is 00:03:51 my storage, right? So it's no different than a refrigerator, for example. You go to the grocery store, you have too much food, you put it in the fridge, right? So now think about it this way. If you now go to the store five or six times a day, and all the time you're putting food in your fridge, pretty soon your fridge is going to be full. Then somebody says, well, in order to empty your fridge, you need to go to the store more often. It's like, does that make any sense? When you're eating, you're literally telling your body, please store some of these excess calories into storage, put it into storage,

Starting point is 00:04:26 because that's what the insulin does. It's neither good nor bad, it's just its job. So because you're stimulating it all the time for 14 hours and 45 minutes of every day, you're telling your body to do that. And it's actually more because of course, your stomach actually holds some of the food and slowly sort of pushes it out.

Starting point is 00:04:45 So the point is simply this. We try and complicate things so much all the time, but it's very simple. When you're eating, you're storing calories. When you're not eating, you're using calories. That's all it is, and that's natural, and it's normal, and you can handle it, which is why it always boggles my mind that you see experts saying,

Starting point is 00:05:05 oh, you know, intermittent fasting is so bad for you. And there are certain circumstances, of course, if you're malnourished, if you're underweight, you know, sure, absolutely. But if you're overweight, if you're type 2 diabetic, that's actually exactly what you want your body to do. Yeah. Let's expand this beyond weight loss because this goes beyond weight, doesn't it? This is actually a very helpful practice for people who want to be in optimal health, have more energy, yes, have a good body weight, but also reduce the risk of getting sick in the future. Yeah, absolutely. Because if you think about it, it's a balance here, right? You eat, you store calories, you don't eat, you use those calories, right? And you want to keep those in

Starting point is 00:05:48 balance. So 12 hours, 12 hours is perfect. If you think about a typical sort of 1960s, 1970s, because, and I, you know, I choose that time because it's before the obesity epidemic and people aren't really watching their diet, particularly people are eating white bread and jam and, you know, stuff like that, right? But if you think about it, you know, you ate breakfast, maybe eight o'clock before school, and then you had dinner, maybe around six o'clock, that's a 10 hour eating window, and 14 hours of fasting. And literally everybody did that every single day without even thinking about it. So was it hard? No, because that was sort of your baseline. And the point is that it's

Starting point is 00:06:31 neither difficult. It's just about your habits. Then all of a sudden, people switched and changed. It was all very inadvertent, I think. It all came back to sort of the dietary guidelines, which was in the 70s, people said, you know, you should eat ultra, ultra, ultra low fat. And in order to do that, the United States government encouraged people to eat processed food because you could process the fat out of it and put other things, mostly carbs, because fat and protein tend to go together. And so instead of eating, say, a typical breakfast of eggs and bacon, which would keep you full until lunch, they'd eat two slices of white bread and jam and some sugary cereal. The problem with

Starting point is 00:07:18 that, and we know this, of course, is that insulin spikes up very high, glucose spikes up very high because they're all very highly refined carbohydrates. Then it crashes. So by 1030, you're just starving. So then you go get yourself a low fat muffin. And then the same thing happened. So people started eating more frequently because they were basically just eating a whole bunch of refined carbohydrates. Then they said, well, I'm eating six times a day when I used to eat three times a day. But since I'm eating super low fat, this must be a good thing. It never was a good thing, of course. It was just a byproduct. Now, of course, we know we shouldn't be eating a whole pile of refined carbs. So I think that's sort of how it came about because of this sort of insistence that we eat low fat, low fat, low fat, which

Starting point is 00:08:06 unfortunately wasn't like more beans. It was refined, highly refined carbs is what replaced the fat in our diet. But then the inadvertent thing was that even as we moved away from those refined carbohydrates, so we started acknowledging, hey, there's healthy fats. Hey, you should eat nuts. Hey, you should eat whole grains. Even as we moved away from those refined carbs, we never moved away from the fact that we're just eating all the time. Yeah. Well, if someone's kind of heard what you've had to say so far and is thinking, okay, all right, I'm interested in trying intermittent fasting, where would you encourage them to start yeah i think that the first place to start really is just to go back to sort of eight hours ten hours of eating if you

Starting point is 00:08:53 want to eat sort of breakfast at eight nine o'clock in the morning and finish by like six o'clock in the evening and then let the rest of the time be fasting. You know, you're talking about an 8, 9, 10 hour eating window. It may be 14 to 16 hours. And that's relatively easy to do. And of course, it's something that people have done for many, many years. So cutting out the snacks, cutting out the late night eating, and push your breakfast a little bit later, then you're automatically going to get that period of time. And that's a great place to start. And then you can experiment, you can go longer or shorter, depending on what you like. So you're saying start off for people, maybe a 10 hour eating window, as you say,

Starting point is 00:09:36 let's say 8am till 6pm is your eating window. Out with that, what, in your view, because you take a lot of people through these fasting programs, I know, in your clinic, what are they permitted to do outside that eating window in terms of drinks and other things? That's the first question. And then going beyond that, it's like, what benefits then might people, once they start there and go, fats, it's like, what benefits then might people, once they start there and go, okay, this is pretty easy. I can do that. I'm feeling better, lost a bit of weight. I'm sleeping better. I feel lighter. Why should some people consider going further? Because I think in your clinic, am I right in saying that sometimes you take people into 36 hour fast, 48 hour fast? Yeah. So, you know, classic fast is water only, but really you don't have to be

Starting point is 00:10:26 that strict. There's no rules. Like, uh, you know, when you're talking about fast and there's two main variables, one is the length of fast and two is what is allowed during that fast. So tea, for example, is something that I recommend for a lot of people. Um, you can drink coffee and then those really don't have too much effect on, you. There's no calories in green tea and it really doesn't have much effect. So teas, coffees, herbal teas, those are all great to do. like bone broth, for example. And then people even take like small salads and stuff within that fasting window, you know, if they get very hungry, for example. And those are, you know, people think, well, you know, I just broke my fast, right? I have to start all over. That's not what happens. Because what happens is that when you're fasting, you're trying to force that insulin level down. So if your insulin level is going down, your body is going to switch towards using your stored calories, not the food.

Starting point is 00:11:27 If you break that fast with, say, some bone broth, yeah, your insulin is going to blip up for a little bit, but it's a very small amount. And then it's just going to start going back down again. It's not going to have a huge effect. So, even if you take something during that fasting, it doesn't mean that all of your progress has been lost and you have to start from scratch again. So you don't have to worry so much. And then the other thing is in terms of the benefits of fasting, why continue with it? There's a lot of reasons. Like if you think about the physiology of what happens during fasting, there's a lot of good things that happen. People always assume that they're going to be tired during fasting, but that's not actually what happens. So if you don't eat, there's a very sort of stereotyped response that is insulin is going

Starting point is 00:12:12 to go down, but certain other hormones are going to go up. And one of those hormones is the sympathetic nervous system and growth hormone. So both of those go up as you fast. Parasympathetic is sort of relaxing. Sympathetic is sort of stimulating. It's a sort of fight or flight response. So you actually activate the sympathetic nervous system when you don't eat. And this is sort of basic first year medical school stuff. It's a number of hormones called the counter-regulatory hormones. You get a spike of this counter-regulatory hormone in the morning, around 5 a.m., 4 a.m., 5 a.m., and it sets you up for the day. It's pushing the calories, the energy into the system so that you have energy for the

Starting point is 00:12:53 day ahead. So that's why you don't necessarily have to eat the minute that you get up because your body's already started fueling yourself from its stores. And because you're having higher levels of sympathetic nervous system, you're going to be able to concentrate better. You're going to have more energy as you fast, not less energy. Like a lion who just ate, it's sort of sleepy, just wants to lie there and digest, but you have a hungry wolf. Is it sort of like falling over because it can't concentrate? No. The hunger is what makes it dangerous because it's dialed in, it's concentrated, and it's got energy to burn. It's just getting its energy from its stores, not from its food.

Starting point is 00:13:33 And that's because, again, it's not some voodoo magic psychology. It's just physiology. Your body is ramping up at the time that you're fasting. Well, that's great. You've now finally allowed your body to access the stores of energy by allowing insulin to fall by fasting. You're allowing your body to access this huge store of calories, this 100,000 calories that you've had stored away that you've never been able to access before because insulin is always blocking you. Now you have access to this energy they're like well okay let's use it let's

Starting point is 00:14:09 use it your body's pumping up the the sympathetic tones we know that people you know in terms of their mental abilities are do better with fasting so it's a fascinating process but a lot of good stuff there it's it's just crazy how many people have never, ever experienced anything like that because of what we were talking about right at the start of this conversation where over 50% of the US population who don't work in shifts are consuming foods over 15 hours a day. So they're nowhere near able to actually experience these things. The benefits go far beyond just weight. So there are implications for your gut function. Often I've found people with IBS type symptoms, it really clears up massively when they have periods of fasting. Sleep can improve, you know, all kinds

Starting point is 00:14:58 of things. Other things can benefit. So, you know, I definitely encourage people to experiment and see. benefit. So, you know, I definitely encourage people to experiment and see. Right at the end now, Jason, in all your years of experience, what are some of your very best tips for people who have heard what you had to say go, right, I'm in, I want to make some changes. What practical advice have you for them right at the end here? The most important thing, I think, is to focus on foods and less on nutrients like carbs or that kind of thing. Focus on eating whole foods is still probably the most important thing. It always comes back to eating natural foods and eating in a way that's not constantly stimulating. So, you know, to me, it's relatively simple and not that controversial. One, don't eat too much sugar. I don't think that's very controversial. Two, try to eat unprocessed foods, which again,

Starting point is 00:16:00 I don't think is all that controversial. And three, don't eat all the time. If you're overweight, don't eat all the time. Cut out those snacks. To me, it just seems like, hey, this is just what it was in the 1970s. There was none of this count your carbs, count your calories, count this, count that. Eat whole, unprocessed foods, whether it's vegetables or even meats. Enjoy your foods when you do eat them, but don't eat constantly. Give your body a break once in a while. So those three things, I think, are still the core of everything without getting too complicated.

Starting point is 00:16:36 Don't eat too much sugar. Eat unprocessed foods and don't eat all the time. Hope you enjoyed that bite-sized clip. Hope you have a wonderful weekend. And I'll be back next week with my long-form conversational Wednesday and the latest episode of Bite Science next Friday.

Feel Better, Live More with Dr Rangan Chatterjee - BITESIZE | Why Intermittent Fasting Works | Dr Jason Fung #373

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