How To Burn Fat, Heal Your Metabolism, and Live Longer

Mark Hyman, MD

Dr. Mark Hyman is leading a health revolution—one focused on using food as medicine to support longevity, energy, mental clarity, happiness, and so much more. Mark Hyman, MD is a practicing family physician and an internationally recognized leader, speaker, educator, and advocate in the field of Functional Medicine. He is the founder and director of The UltraWellness Center, Founder and Senior Advisor for the Cleveland Clinic Center for Functional Medicine, a fifteen-time New York Times best-selling author, and Board President for Clinical Affairs for The Institute for Functional Medicine. He is the founder and chairman of the Food Fix Campaign, dedicated to transforming our food and agriculture system through policy.

He is a co-founder and the Chief Medical Officer of Function Health. He is the host of one of the leading health podcasts, The Dr. Hyman Show with 150+ million downloads. Dr. Hyman is a regular medical contributor to several television shows and networks, including CBS This Morning, Today, Good Morning America, The View, Fox, and CNN.

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Full Transcript

Automatically generated. Please forgive any typos or errors in the following transcript. It was generated by a third party and has not been subsequently reviewed by our team.

Introduction:
Coming up on this episode of the Doctor's Farmacy.

Dr. William Li:
We are not born to suffer a bad metabolism, and we can take steps to beat the need to have these extreme diets that wind up being unsustainable anyway.

Dr. Mark Hyman:
Welcome to Doctor's Farmacy. I'm Dr. Mark Hyman, that's farmacy with an F, a place for conversations that matter. And if you struggle with your weight and metabolism, you've tried a lot of things, you're a bit confused and you want to know the latest and the greatest from the science. Well, you're going to learn it today because we have as our guest, an extraordinary scientist, a good friend of mine, a guy who wrote an amazing book that taught me so much called Eat to Beat Disease and has written another book called Eat to Beat Your Diet: Burn Fat, Heal Your Metabolism, And Live Longer. We're going to talk about that today. He's an incredible physician, a detective of medicine, a scientist, author of the New York Times bestselling book we mentioned, Eat to Beat Disease. His groundbreaking and research has led to the development of more than 30 new medical treatments that impact more than 70 diseases including diabetes, blindness, heart disease, and obesity.
His TED Talk, Can We Eat to Starve Cancer? Has garner more than 11 million views. That's amazing. He's been on lots of shows, Good Morning America, CNBC, Rachel Ray, Live with Kelly and Ryan. He's been in USA Today, Time Magazine, in Atlantic and he's president and medical director of the Angiogenesis Foundation and is leading global initiatives on food as medicine, which is definitely something we have in common. So his new book is out, get it wherever you get your books. And I'm so excited to dive into this topic of metabolism, health, fat, all our missed and misconceptions and what the science actually shows. Welcome William.

Dr. William Li:
Thanks Mark. It's a pleasure to be here. And we got so much to talk about because we've got so much in common.

Dr. Mark Hyman:
We do, we do, we do. It's pretty cool. There's just an amazing amount of misunderstanding and misconceptions about our metabolism. What is our metabolism? How does it work? What are the things that people have gotten confused about when it comes to fat and metabolism? What are the top misconceptions?

Dr. William Li:
I think it starts all the way back to how we think about our bodies and metabolism and body fat and how they're all kind of intertwined. Because all of us have had this experience where you step out of the shower in the morning naked and out of the corner of your eye, you see the mirror and you see a lump or a bump that you don't want to have there. Then you step on the scale-

Dr. Mark Hyman:
I never do. What do you mean?

Dr. William Li:
And the point is that we wind up cursing, I think, body fat and we start thinking our metabolism isn't actually working on our behalf. And that's actually just completely incorrect. Our body fat and our metabolism are so tied together in ways that give us health, generate our health. And what I wrote about in my book, Eat to Beat Your Diet is really the new science of the metabolism, some of which is only 24 months old. It is brand spanking new research that is changing and upending everything. We used to think about human metabolism and how that connects to body fat, good and bad. And then the really exceptional part of this is that guess what? We don't need to fear our food. We can actually love our food in order to be able to up our metabolism. So where do you want to begin?

Dr. Mark Hyman:
Well, I love that. I always say love the food that loves you back. A lot of times we love the food that doesn't love us back. But the good news is there's lots of food that loves us and that we love. So I think that's great. So the myths are things that have to do with people's view of why we gain weight, how our metabolism works. I'd just like you to sort of unpack that a little bit. Because I think I want to get to what we got wrong and then we'll talk about what we can do right.

Dr. William Li:
Yeah, that's a great place to start. So first of all, I'm a scientist as well as a physician and as a scientist, I'm always interested in the origin story. Where do things come from and how does it actually develop over time? And now I'm going to kind of give you the mic drop research that occurred just published just 24 months ago. The largest human and most ambitious study of human metabolism ever undertaken in history was published two years ago in the journal Science, which is the top one of the top medical journals. It was led by a guy named Herman Pontzer who is at Duke University, and he worked together with 90 other collaborators. So this is a big research project. And they looked at and they recruited subjects from 20 countries, every continent. And in total they had 6,000 people. And what was really remarkable is they studied metabolism in exactly the same way.
So that's one very unique aspect of this, to study 6,000 people, human metabolism in exactly the same way. The way they did it, by the way, is they gave them a drink of water. Water is H2O, H being hydrogen and O being oxygen. And at what the researchers did, they tweaked the hydrogen and they tweaked the oxygen very minimally, but that you can detect it so that when people drank this cup of water, their metabolism worked its magic on hydrogen and oxygen. They could measure it in their breath, in their blood, in their urine. So they asked a question, what was human metabolism across 6,000 people? And what was really remarkable is this question was asked because they studied people that were two days old newborns and they studied people that were 92 years old at the tail end of life. So 6,000 people over the entire human lifespan.
And I know that we've just been talking about lifespan, right? That's really what you've written about in Young Forever, and in this whole lifespan the question is how does your metabolism change? That's one of the things we've always had an assumption about. And I think that you and I, when we went to medical school, we were taught the rudimentaries about metabolism, the biochemistry, but we never had any of the nuances of how it changes over our life. So most people, we assume that some people are born with a slow metabolism, some people are born with a fast metabolism, and some people are skinny and don't have to worry about eating what they eat, and other people are struggling with their weight and they have to fight with their food. Same kind of assumptions I think that many people carry around. That's a myth because it turns out that, let me tell you what they did in a study.
When they looked at the metabolisms, they looked at, what they found in the beginning is that the metabolism was all over the map for 6,000 people, just what you'd expect. But we now live in the era of artificial intelligence and super computing. So they developed an algorithm that would go to every subject and correct the result of the metabolism on the basis of excess body weight, excess body fat, so they could remove the effect of excess body fat every individual 6,000 times. All right? Now you got to remember 6,000 people over 20 countries. That's men and women, young and old, different race, racial backgrounds, different body sizes, different eating patterns. And what they did when they removed the effect of metabolism, excess body fat, it was like pulling the cloak off the statue of David. They found that all humans go through only four phases of metabolism in their entire life. We are hardwired. This is revealing the operating system of your laptop.

Dr. Mark Hyman:
Wow. Tell us, tell us. I'm so excited.

Dr. William Li:
So the four phases, everyone is born with the same metabolism. In the first phase, it's zero to one. Human metabolism is skyrockets so that at one year old, when you reach 12 months, your metabolism is 50% higher than what it would be later when you're an adult. All right? So it's like a rocket ship blasting off. Phase two, that's from one year old to 20 years old. Your metabolism goes down, down, down, down, down, down. Now why is that important? Because most of us who have had kids assume that when your teenagers are eating two meals and bouncing off the walls and growing like a bean sprout, their metabolism must be going up, right? Wrong.

Dr. Mark Hyman:
It's going down.

Dr. William Li:
It's going down. And it descends to adult levels. That's phase two. Phase three is starting from 20 to 60, and you know what the result was? This is the most surprising part. 20, 30, 40, 50, 60, metabolism's hardwired to be a straight line. It does not change as the hard wiring in our body. And what that means is that 60 can be the new 20 if you allow your metabolism to do it's thing. All right? That's phase three.
Now I'm going to come back to that in a second. And then phase four, the four phase is from 60 to 90, you do decline a little bit, but only by 17%. So by the time you're 90, all right, your metabolism's basically only less than 20% decreased from what it was at 60 or at 20. All right?

Dr. Mark Hyman:
That's amazing.

Dr. William Li:
It is amazing now, and basically what this discovery has done is led us to completely rip up the old metabolism textbooks and the new ones are being rewritten right now based on this new science. Now, the key part though, because people say, well, wait a minute, I'm 40 years old, I'm 50 years old, I'm gaining weight. I know this happens.
What happens is that when you add the data back, when you add the effect of extra body fat back, you crush the metabolism. So it's not that a slow metabolism causes you to gain body fat and gain weight. It's the other way around. Our body fat, our metabolism runs this way. But if you undertake behaviors, whether you're inactive, you're not getting enough sleep, you're overly stressed, you eat in incorrectly, your microbiomes deranged, what happens is you gain body fat. And it's body fat that crushes your metabolism completely the other way around what you thought.

Dr. Mark Hyman:
Wow. So being overweight slows your metabolism down,

Dr. William Li:
That's right. So the good news, by the way, with this discovery is that it means that suddenly we have a new ability, a new found ability to be able to control our metabolism. Because if we can actually right size our body fat, because this is the other point, fat isn't our enemy. Fat's in fact a critical part of our health except when we have too much of it. So what you want to do is sort of shave it back down, tune it down, turn the volume down, and as you do that, your metabolism rises because that's the hard wiring in our body.

Dr. Mark Hyman:
So proportional to your weight, your metabolism rises is what you're saying?

Dr. William Li:
That's right. And body size, and all depends on your body size as well. And by the way, this is important because body size is often viewed as sort of the lead balloon when it comes to the bummer of metabolism. But that's not really the case. If you look at some of the healthiest people in the world, and I write about this in my book, think about Olympians. You have the little gymnasts, you've got the shot putters, you've got the weightlifters, and they're all champions even though the body sizes are different. And then if you look at boxing, there's like 14 different weight classes from flyweight to heavyweight in, and there's a world champion in every single group. And so those people are super fit. And I think this is the other thing is we need to do is to realize our metabolism is like the operating system in our laptop, whether you got a 15 inch or a 13 inch laptop, this operating system is still at work. And so what happens is that when we accumulate excess body fat, that's like confusing your computer and getting it glitchy, then you got to actually clean that up. And I think this is really what there's an opportunity for us to do is to clean up our operating, our body of excess body fat to allow our operating system when it comes to metabolism to be able to run the way it wants to run.

Dr. Mark Hyman:
So then what you're saying essentially is that excess body fat will create a slower metabolism. The question then is what is causing us to gain the weight? And what do you mean by metabolism exactly? Because I think people have different conceptions of what that means, and I think there's scientific definitions and there's the common sort of understanding of it, which are a little bit different.

Dr. William Li:
Yeah, no, no. Listen, and by the way, this term metabolism is a term that everyone thinks they understand. Even doctors. So and I, when we sit over coffee or lunch and we talk about metabolism, we're pulling out, we're busting out the standard accepted scientific definition of the net sum of all the chemical reactions in a body, et cetera, et cetera. But I have I think maybe a different, in a more contemporary way that people can relate to. So everyone has a car, and in a car you just assume as you're driving your car that it will actually take the energy to power up the engine so you can get from point to point, right? That's what we do. And that's frankly our metabolism, it's the process by which our body drives our engine in our body gives it energy to go around. We don't normally think about it, just like you don't think about the energy in a car, you're just going about your way.
Now the analogy of the car is really useful to think about because when you're driving in a car, you do keep your eye on the fuel gauge. And when the fuel gauge runs low, what do you, you pull over to the filling station, take out the pump, the nozzle, put it into the tank, and you repress it, you fill up the tank goes click, no more gas comes out and you drive off. Okay? Now same deal in our body. When our body uses fuel, our fuel in our body for energy to drive the engine of our body comes from our food. Our food gives us our fuel. So we don't have a fuel gauge in the same way that a car does, but our brain senses it and our organ senses so that when our fuel gauge runs low, we don't pull over to the filling station, we pull over to the dinner table or is the refrigerator-

Dr. Mark Hyman:
7-11.

Dr. William Li:
Hopefully not to the 7-11, but the idea is that we pull over to have to fuel up. All right? Now, when we eat food, it's kind of like going to the filling station. And I want to first give this example. Imagine if you're filling your tank in your car and the gas tank filled up, but that at the end it doesn't click when the tank is full. You know what would happen is that the tank would fill it would overflow, the gas would come down the side of the car around your tires, pool around your feet, and you'd be standing in a dangerous, toxic, flammable mess, all right? And what would happen is you have to step away and wait for the air to blow it off, evaporate it. But our body isn't quite as cleverly designed. We don't have a clicker that's an off switch per se.
So we can sit pulled over to our filling station to fill up on food as our fuel, but we can eat and fill up and fill up and fill up and not stop. And so one thing, when we don't stop, we are literally overloading our fuel tanks. So let's talk about the fuel tank for a second. All right? We need that energy from our food, let's call it calories, but I don't want people to count calories or think about calories in and calories out it. When you say the word calories, people kind of go in a certain direction. I just want to talk about fuel. So basically what happens is that when you're putting food in your mouth, your pancreas makes it insulin. Insulin is elevated and basically it helps us draw the energy into our cells so we're able to operate.
If you've got extra fuel, what happens is your body takes that extra fuel and it slows it up into fat cells. Now we are born with fat cells that formed in our mom's womb, and they formed not to make us look bloated, but our fat cells at birth basically were our fuel cells preparing for later on when we needed to store energy. Now, fat cell can actually blow up when you store it with fuel by about a hundred times in size. But when that sink's filled up and you eat more food, your body has to fill up another fat cell and yet another fat cell. The more you eat, the more fat cells have to be filled up to a hundred times their size, and when you run out of fat to fill up, you need a more fuel tank. Your fat cell goes to stem cells to make a new fat cell and fill that up as well.

Dr. Mark Hyman:
Oh wow. That's terrible.

Dr. William Li:
That's like going to the gas station and just floating up jerrycans of gas and stuffing your pickup truck with them and piling it high. And so what happens is that we can easily overeat and gain body fat and therefore gain weight just for that reason. So that's one explanation for the body fat.
Now the other issue with regard to that, back to the car analogy, the quality of the fuel we put in our car matters a lot. We want to put the highest quality gas into our gas tank in order to be able to run our car as long as we can. And if you basically put some crappy gas, low octane gas into your car once in a while, no biggie, the engine's going to run. But if you did it for a whole lifetime of the car, it's not going to run as long or as well. Same deal with our metabolism over the course of our lifespan. If we put high quality fuel in, nutrient dense foods like plant-based foods, high quality sources of protein, we are actually taking care of our engine. And of course, you don't want to eat too much, but if you put low quality fuel, ultra processed foods, all those artificial preservatives and flavorings and colorings, what we're doing over time is we're poisoning our engine, including our metabolism.

Dr. Mark Hyman:
Wow. So basically what you're saying is that this fat just kind of accumulates and then it slows our metabolism and it's kind of a vicious cycle.

Dr. William Li:
Yeah.

Dr. Mark Hyman:
But you also said we shouldn't be so afraid of fat in a way, fat isn't necessarily the villain we thought it's supposed to be. So what's true about that paradox that you're highlighting in your book?

Dr. William Li:
It's actually not a paradox. It's really about balance and homeostasis, like so many other things in the human body. So I like to tell people that when your dad's sperm met your mom's egg in the womb, and you were just a bottle of cells starting to form your future body, the first tissue gets laid down is your circulation. And that's what I study, angiogenesis, because every organ needs blood supply. A second tissue that gets laid down are your nervous system, because every organ needs the ability to go have the wiring, to get instructions through this nerves that to do something. All right? The third tissue that gets laid down are little fat cells. They're called adipocytes. And the interesting thing, Mark, about where these form, they form around blood vessels. The first fat are laid down like bubble wrap, like a layer bubble wrap around blood vessels. And the reason why it's preparing for later in life when you're eating food, the energy, the fuel from your food has to be stored and its best to put your fuel tank where the fuel's coming in, by your blood vessels.
So we're actually born with our body fat long before we had a face that we could stuff with food. So we got to ask that question, why do we have body fat? And by the way, is it always harmful? Answer is no. Because if you take a look at fast forward nine months, newborn baby makes everyone smile. You know, want to actually, you want to pinch, its chubby cheeks. Healthy babies are chubby, tubby, they've got big cheeks, big tummies. They're arms and legs look like those balloons that a circus clown makes the little poodles out of. They're big, right? Okay. And so fat actually in a baby is healthy. In fact, if you saw a baby that had chiseled cheeks like a runway model, long thin arms, a long thighs, you'd be freaked out. You'd say there's something seriously wrong with that baby, right?

Dr. Mark Hyman:
Yeah, it would look very sick. You want those chubby fat cheeks.

Dr. William Li:
And so that's one of the things that I think is so important for people to understand is that fat is not our enemy. We had our body fat for a long time. And so what are the roles of body fat as we grow up? I mean, basically, I will put a little footnote to say as every little boys and girls all look the same, but as we go through puberty, it's really our body fat that kind of shapes us. So the female form that classic form, actually, you get a little skinnier in the waist, less subcutaneous fat, guys that you get a little bit bigger, they get a little more visceral fat, hips get bigger, breasts, butt, all those, it's a fat reshaping it. So if you were to think about the human body being made by Michelangelo, back to that statue of David, body fat plays a big role in that.
However, let's talk about for any person, not just sort of the idealistic figure. Here's the four things that body fat does. Number one, it's a cushion. And if we didn't have body fat, if you tripped on a carpet and you fell on the ground, your organs could split open. So thank goodness we have a little bit of cushion.

Dr. Mark Hyman:
Sounds terrible.

Dr. William Li:
Right? Number two, what is it? It's a fuel tank like we talked about. You need to actually have your fuel. So your body fat is critical for your metabolism. It's part of our metabolism, it's a fuel tank that stores our food. The third thing that body fat does is quite remarkable. It's an endocrine organ. In fact, it's the biggest endocrine organ in the body. Endocrine organs like your thyroid, your adrenal glands, like your glands, your ovaries, and your testicles. To think that body fat's an actual organ is a kind of stunning thing to think about.

Dr. Mark Hyman:
Just like your muscles are an organ, right?

Dr. William Li:
That's right. That's right. So here's the endocrine, hormonal function of healthy body fat. All right? This is like to keep you alive, you have to do this. There's about 15 organs that, at least 15 organs that we now know that body fat as an organ makes, healthy body fat. One of them is called leptin. Okay? Now leptin people think about it as a satiety hormone. I prefer to explain it as a volume switch. When the leptin is elevated, you don't feel so hungry. When the volume is down, you feel a little hungrier. And so actually it's not a light switch to go up and down. You turn it on lights and off. It actually goes up and down. Like so much of the body and hormones go, they're kind of a feedback loop. So a little bit higher, a little bit lower, that's leptin. And by the way, when you're hungry, what do? You pull over to the filling station to fill up. So very important for our metabolism.
Second, there's a hormone called adiponectin. If you and I saw patient and ordered a vial blood, it's standard vial blood to be sent to the hospital lab to measure all the hormones in the body, a hormonal panel. There'd be the thyroid, there'd be the cortisol, all the other hormones, testosterone. There'd be one hormone, adiponectin, made by healthy body fat that is 1000 times higher in your circulation than any other hormone. And the reason it's so high is adiponectin is part of your metabolism. It works, it collaborates with insulin to make your energy extraction from your blood, from your food and your fuel back into your cells more efficient. And so when you have a lot of adiponectin, you're capable of getting that energy in when you're eating, which is so important.
And then there's another, and if adiponectin is kind of the gas pedal for this, for efficiency, a third hormone called resistin is the brake. Adiponectin draws in more energy, not so fast, resistin goes there. So again, balance. Think about driving on a highway on a four lane highway. Every now and then you got to get into the fast lane, adiponectin goes on, but then there's a car coming up. So you got to slow it down. These hormones are naturally functioning along with leptin in order to be able to tell us to go to the filling station and how we fuel up and how fast we actually feel fuel up. This is normal. That's incredibly, that's a third role of fat. And the fourth roll of fat, which perhaps is one of the most surprising, and you hear about this in a fitness world, but is that your fat can also be a space heater.
And by space heater, I mean that there's a special kind of fat called brown fat that will ignite and fire up by drawing down fuel. Now, this is kind of like the gas burner on your stove top. So what do you do? You hit a striker and it goes whoosh. And you wind up having a flame that's like brown fat and what it does in order to get that flame, it's drawing the energy from your other fat cells. So it's brown fat, good fat, drawing on the energy to burn down bad fat. We'll have a little demo here for your guys. And I show it is that, think about brown fat like this. It's like a torch and you turn it on, you're actually, this is brown fat. It is burning down fuel. Where's this fuel coming from? It's drawing this fuel when it's turned on from your white fat. And so this is how you can actually use one type of fat to fight another type of fat. So those four functions of body fat really help us re conceptualize, like don't fear it, but tame it.

Dr. Mark Hyman:
So is there way to activate brown fat with food? Because we know how to activate it for example with cold therapy, because often cold plunges increase metabolism, may improve insulin sensitivity, and they've been shown to actually help speed up your metabolism and burn white fat, which is the kind you don't want. So can you take us down that road if there's anything that we can do other than laying in a 40 degree cold plunge to activate our brown fat?

Dr. William Li:
Yeah, well look, I don't know you-

Dr. Mark Hyman:
Although by the way, I think people should do that, but yeah, it's not everybody's cup tea.

Dr. William Li:
Well, I mean, what's interesting is how brown fat was discovered because it was discovered in humans. We've known for hundreds of years that there's a little bit of brown fat in animals that hibernate, which means that they're sleeping in cold temperatures and they need warmth. And so the brown fat in hibernating animals actually fires up and it provides their heat by drawing down the fat that they've stored when they're actually eating, getting ready for the winter. Okay. So in humans, brown fat was actually discovered in a Boston hospital with a female patient who had a tumor in her chest and they had a PET scan that of this woman and PET scans look at metabolism, right? We're talking about metabolism. And guess what? This little tumor in her chest lit up like a Christmas tree. It was really metabolically active, so they didn't know what it was.
But when they biopsied the tumor and they looked at it under the microscope, it turned out to be brown fat. Brown fat was thought to be in children for a little bit behind their shoulder blade. Most people thought that's not in adults, but here was an adult with brown fat. And so what the researchers did at this Boston Hospital, Ronald Kahn, they went back and they said, maybe other PET scans are showing brown fat and we just haven't been looking for it. So he went back and looked at 1000 PET scans of adults that were getting scans for lots of different reasons. And he went to look for the brown fat signature. And guess what? He found it in about half the people. And so he's like, well, that's interesting. It seems to be present. But what he found out is that it became much more noticeable when the people who are getting these PET scans were getting their scan in the winter in Boston when it's cold.
So getting a PET scan in the summer, the brown fat doesn't light up as much, but cold temperature definitely fires it up and it's all over adults. And so basically they were able to characterize, and this is a big program at the National Institute of Health, now with the NIH, they're actually figuring out where human brown fat is. They've profiled it. And actually the researchers actually gave me the photograph, gave me permission to publish the photographs in my book, Eat to Beat Your Diet, some of the first pictures ever of brown fat.

Dr. Mark Hyman:
Really?

Dr. William Li:
So lumpy, bumpy white fat, which is the harmful fat is lumpy, bumpy. It's the stuffed jiggly stuff under your arm, under your chin. It's the muffin top. Okay?

Dr. Mark Hyman:
Yeah.

Dr. William Li:
And the visceral fat, by the way, also lumpy, bumpy, but you can't see it because it's inside the tube of your body. Brown fat isn't lumpy bumpy. It is wafer thin, it's paper thin, and it's not near the skin. It's close to the bone. And where is it in the body? And this is what's really cool about the imaging studies. It's plastered around the side of your neck is behind your breastbone, it's under your arms and a little bit in your belly.

Dr. Mark Hyman:
And behind your back and your shoulder blades?

Dr. William Li:
A little bit behind your back and your shoulder blades, but a lot under your arm. Kind of like a bra. Okay. And a lot under, exactly. So think about it, right? This is how we stay warm in the winter, right? So what's really cool is that as they've been teasing out the mechanisms of how cold actually stimulates brown fat, turns it on, it turns out it's the same pathways that foods can turn on the same pathway. So basically here it goes.

Dr. Mark Hyman:
Yeah, let's talk about that.

Dr. William Li:
Your brain releases norepinephrine, which is kind of a stress hormone really, when you get into that cold bath, right? Like you go, whoa, right?

Dr. Mark Hyman:
Yeah, exactly right.

Dr. William Li:
Jump into the ocean, you go to the beach and the water's cold. Whoa. And that whoa tells your brain to go release stress hormones. And what happens is that the stress hormones run down the nerves to the rest of your body. But when they get to your brown fat, some of the nerves go to your brown fat, it fires them up. And it makes a lot of sense because you're trying to warm up for it. So we now know that norepinephrine will actually bind to a receptor and brown fat called the beta three adrenergic receptor. This is a very well known switch on our body.
And anything that can trigger that switch, like hot chili peppers, like mushrooms, like sulforaphanes in broccoli, can trip that switch, that beta three adrenergic receptor. Then what actually happens is that there's a domino effect inside our brown fat, that wafer thin fat, the beta three edge adrenergic receptor, when it fires off, when that light switches turned on, it sends another signal, it's like dominoes. The next domino it turns on is something called UCP1, uncoupling protein one. So the hormone triggers off the switch called beta three adrenergic, which then triggers off another switch called UCP1. UCP1, by the way, is on top of the mitochondria. And I like to actually, which is in brown fat. And I like to tell people, and I'm sure maybe you had your own word for this, but when I was memorizing all the stuff in medical school, mitochondria, which is a fuel cell, an energy cell inside, like a battery inside all of your cells, I called it the mito, mighty chondria.

Dr. Mark Hyman:
Mighty chondria.

Dr. William Li:
Because it actually is like a fuel cells. It's like a nuclear power plant. And when that adrenergic receptor trips that light switch ab beta at the UCP1 on the mighty chondria, the mitochondria, it fires them up. And guess what? Mitochondria of has a lot of iron in it. The element to iron, the metal iron, and a lot of iron, by the way, packed together is like rusty nails. It's colored brown. Iron tends to oxidize as brown.

Dr. Mark Hyman:
Oh, interesting.

Dr. William Li:
That's why brown fat is brown.

Dr. Mark Hyman:
Wow.

Dr. William Li:
Because it's got so much fuel cells with so much iron, it looks brown. I'm a scientist. I asked the whys, right?

Dr. Mark Hyman:
Oh wow. That's interesting.

Dr. William Li:
Like why is brown fat brown.

Dr. Mark Hyman:
That's a good question. I never thought of that.

Dr. William Li:
Right? That's the answer, right? Okay. So it turns out that anything that turns on that beta three adrenergic switch, cold weather can do it. There's a bladder spasm medicine called mirabegron that if you actually, that also specifically designed to hit that switch on your bladder, but guess what? Researchers have actually shown, it'll hit that switch on your fat cells, fire up your brown fat as well.

Dr. Mark Hyman:
Is that why you have to pee when you're cold?

Dr. William Li:
Well, but they did that experiment to show this mechanism at really high doses, so I don't recommend anybody you try to use mirabegron to actually fire up their brown fat. But it turns out foods like chili peppers, like avocado, like walnuts, capers, are all capable of firing off this switch. And so what I do in my book is in the research that went into this is like there's 150 foods that have been discovered along with the doses of how much it takes to fire off your brown fat.

Dr. Mark Hyman:
Really? Like what foods?

Dr. William Li:
Well, one thing is sulforaphanes, right? So sulforaphane containing foods like brassica, broccoli, bok choy, cauliflower, that entire cat, Swiss chard, all of those substances containing plant-based foods containing sulforaphanes will fire up your brown fat. So will the beta d-glucan in mushrooms. White button mushrooms, shiitake, enoki, maitake, right?

Dr. Mark Hyman:
I feel good about my dinner last night because I had [inaudible 00:33:45] and shiitaki mushrooms.

Dr. William Li:
You were firing up your brown fat, right?

Dr. Mark Hyman:
Okay.

Dr. William Li:
So, and by the way, as I went through the entire catalog and I wrote my whole section about food in this book, imagining for my reader that I was taking them through the grocery store and the shopping cart as if they were a kid. You know like when you were a kid, you hopped into your mom's shopping cart and she was pushing it along. Except this time what I'm doing is as we're going through the different sections of the grocery store, I'm telling you what to pull out that will activate your metabolism at burning body fat and put it into your cart. Produce section, the forbidden middle isles, the seafood section. The beverage section. It literally is a, it's like a tour of your grocery store to what to shop like a shopping list for metabolism.

Dr. Mark Hyman:
Yeah. So shiitake mushrooms and mushrooms, the broccoli family, what else activates brown fat?

Dr. William Li:
Okay, so one of my favorites-

Dr. Mark Hyman:
Because this is important because what you're saying essentially is that we don't activate our brown fat enough because we don't have cold exposure. We don't need certain foods that are meant to do it, and it undermines our metabolism. And a way to speed up your metabolism is actually to activate brown fat.

Dr. William Li:
Exactly.

Dr. Mark Hyman:
So that's why this is so important for people to listen to.

Dr. William Li:
And by the way, let's do this again. Activating your brown fat with food is turning on your burner, okay? And that you're burning down fuel.

Dr. Mark Hyman:
That's quite a lighter you got there, William, Dr. William, I don't know, are you sure you're not a little pyromaniac on the side there?

Dr. William Li:
No, it's great for a fireplace. But it's a great illustration because people really understand that the strength of that flame has to come from someplace, and that's really the potential of our brown fat. So what are some of the other foods besides the greens, the leafy greens, the kales, the mushrooms, the onions, the red onions I talk about? I actually like to say surprisingly, if you go into the middle aisle of the grocery store, remember we used to always lecture people to stop the perimeter. That's where obviously there's a lot of good stuff. But it turns out there's a lot of good stuff in the middle aisles. It's just buried with all the junks.

Dr. Mark Hyman:
Like sardine cans and olive oil.

Dr. William Li:
Exactly right. And dried apples and capers in jars or in bags, lentils, prunes, not tree nuts, tomato pastes, all these kinds of foods actually have been shown to activate brown fat in the lab. They actually activate metabolic stuff. So all the foods that I talk about in the book have human evidence. So I explained the lab, but then I actually show the human research that actually shows that meaningfully, when you eat these foods over time, like three quarters of a cup of dried apples, like dried apple chips, actually will lead you to lose almost an inch of your waist circumference over the course of a month. All right? And this is controlled studies with placebos, not requiring people to cut their calories or go on a special exercise, just adding foods to the diet while actually trigger these processes to burn down extra energy, burn away some of this fat, the extra energy, shrink your fat cells and unleash your inner metabolism. And some of the most dramatic things, by the way, I think are like navy beans, pre-cooked, ready to eat, canned navy beans, cheap stuff. I mean, people care about how much thing food costs in the supermarket these days. And if you buy a can of, this is from the University of Toronto, they studied men eating three quarter a can of beans, three quarter, three quarters of a cup of can of beans five days a week. And compared to-

Dr. Mark Hyman:
Of any kind of beans or?

Dr. William Li:
Of ready to eat navy beans kind, you would make bean soup or a stew out of. And it turns out that just a little under a cup, three quarters of a cup, five days a week over the course of a month shrank their waist circumference by an inch. Now, waist circumference is a good surrogate of the amount of harmful body fat you have inside you because the visceral fat is a dangerous fat. The subcutaneous fat is either beautiful or could make you not be so happy with your body shape. All right? But the visceral fat, which you can't see is actually inside the cavity of your body. It's like peanuts, you would pack into a FedEx container, you're shipping light bulbs, you can pack a lot of peanuts in a thin box and tape it shut. The box still looks thin, but it could be bursting with pressure on the inside. And basically, visceral fat is something that whether you've got a big body or a small body, whether you're obviously overweight or whether you're skinny as a stick, you can still have too much body fat.
By the way, here's an interesting little factoid. Where is one of the first places you gain visceral fat, extra body fat when you start gaining weight?

Dr. Mark Hyman:
I would assume your belly, but maybe I'm going to be wrong.

Dr. William Li:
Yeah, well, 90% of people think it's around the belly and reason, understandably, because that's what you would see. I'm gaining weight. You look in the mirror, I've seen it around your belly. But actually that's not so. Turns out that the first place you gain start building body fat, especially the versatile fat is in your tongue. Your tongue can get fat. So if you take a look at the anatomy of the tongue, the tip of the tongue is the cirque du soleil acrobat. It's actually capable of doing all kinds of crazy acrobatics. The middle of your tongue is muscular. It is buff and full of muscle to be able to move food around your mouth. The back third of the tongue is normally marbled like a rib eye steak with fat. And a lot of people don't realize this, but when you gain start gaining extra fat, one of the first places that it starts to grow where it matters, the visceral fat grows in your tongue. You get more marbling in the back of your tongue.

Dr. Mark Hyman:
Wow.

Dr. William Li:
This happens even as skinny people. And in fact, it was studied in Sweden, young women, women who are middle-aged or younger who were thin actually when they started to gain weight and they started to gain visceral fat, they found it was in their tongue. They started snoring. Their bed partners would say, wait a minute.

Dr. Mark Hyman:
Oh wow.

Dr. William Li:
You started snoring. Now why? Because when you're sleeping, you're relaxed. And when you're relaxed, your tongue's relaxed. Your fat tongue is relaxed, it blocks your airways. And guess what? You have sleep apnea. And so even thin people who have a lot of visceral fat, it's not just the diameter of the airway. We used to think it's the tunnel getting narrower, but even your tongue can gain weight. So these are some of these really interesting facts about body fat that we didn't never really even thought about.

Dr. Mark Hyman:
Amazing.

Dr. William Li:
Which is why we need to actually take actions, as you say, to eat foods. If you really want to fight body fat and raise your metabolism, you don't want to fear your food. You want to actually lean into it to look for delicious, healthy foods, eaten at a modest volume, and also eaten at the right time. So it's obviously what you eats important and how you eats important, but when you eat can also make a difference.

Dr. Mark Hyman:
Totally. So the whole problem of body fat is interesting. And I think there's sort of been this conversation over the last few years that we shouldn't be discriminating against people who are overweight, which I agree. And that we shouldn't actually assume that it's bad for their health, that there's this whole body positive movement, healthy at any weight. And this is sort of a narrative that I think, I don't know for sure, but it feels like it's something that's messaging from the food industry because as a doctor treating patients and looking at their metabolism and their biochemistry and their lipids and their glucose, and really doing deep dives on thousands of patients who overweight, I just don't see that. And I think that the question is what's wrong with the data that showed that in some of the studies that we see that if you're thin, as you get older, you have a higher risk of death. And I think there's a new study that came out that showed that we went from assuming that maybe obesity increased your risk of death by two to 5% and more like 90%. And are you aware of this and what's your perspective? Because I have my own perspective, but I'd love to hear what your thoughts are.

Dr. William Li:
Well, two things. First of all, they think this new science of the metabolism invites us all to become radiologists, which is basically, we don't see the actual patient, but we're looking at the pieces of the puzzle to try to figure out what's going on. And that's what going on is really about the overall health and a function of our bodies from a metabolism perspective, I think you can actually be visually agnostic to what an individual looks like. I think this body positivity versus body shaming is really a reaction to maybe the media and the fashion industry over decades past. So I, look, to each his or her own or their own. I kind of try to take a very neutral, I'm a scientist, I'm a doctor. I try to help people just like you. And so one of the interesting things is very clear. I think your experience, as you just said, supports this.
The data shows if you have excess body fat, if you fall into these categories where you have your fuel tanks are too big. And by the way, the other thing I didn't mention, as you load up on the fuel tanks with overeating and bad habits, besides your metabolism crashing, being suppressed, the fat leaks out of the fuel tanks. At some point that fat, actually, the leaking fat accumulates your liver and it's toxic. It poisons your liver. And that's non alcoholic fatty liver disease. Okay? That's an epidemic all by itself. It's like the gas leaking out of the car around your shoes, it's toxic and it's dangerous.
Second, when fat actually builds to a certain mass where it exceeds its blood supply, then excess body fat billowing out is like a tumor. Tumors grow so fast, they can't get enough blood vessels. And so blood vessels are, they're desperately trying to get blood vessels. What happens in the center of the tumor, and I'm a cancer researcher, so I've been doing this for decades. In the center of the tumor, you get necrotic, you get ischemic meaning not enough oxygen, you get necrotic, meaning it actually dies. What happens when something doesn't get enough oxygen and dies? Inflammation.
So the center, like a tumor, the center of burgeoning fat is highly inflammatory and fat inflammation leaks out throughout the body. So now not only do you have the actual fat causing lipo fat toxicity in the liver causing non alcoholic fat and liver disease, but now you've got a whole body full of inflammation, which is why we correlate obesity with diseases of inflammation, diabetes, cardiovascular disease, cancer, neurodegenerative conditions. So that's one thing about overweight being bad.
By the way. The other thing is that when you've got inflammation in a large mass of fat, you derail the hormonal system. Is leptin, is the volume switch of leptin high or low? Am I hungry or I'm not hungry? I don't know. There's too inflammation. What about adiponectin? Should we have more or less energy? I can't tell anymore. There's too much noise in here. And so it gets confused. Resistin? I don't know, breaks on or breaks off, I can't tell. And that's what happens. You basically derail the hormonal function when your fat grows faster than its blood supply and it exceeds and starts to leak its contents.
All right, what about skinny? It's the completely other side sided equation. Ultra skinny is very dangerous. In fact, studies have been done looking at the likelihood of mortality of people on getting a cardiac catheterization, all right, of skinny people versus obese people. It turns out the chances of having a complication and dying as a complication of cardiac catheterizations higher if you don't have enough body mass, why? Basically when you actually have too little body fat, your energy is compromised, you're not making as much leptin, you're not making as much adiponectin, resistin is also not in its normal fashion. And what happens is that you're not able to command the signal. The conductor is missing members of the orchestra and pages are missing from his own sheet music. And what happens is that that actually is a setup for metabolic disaster and healing.
And that's why in my book I talk about healing your metabolism. Look, it's all about balance. We are hardwired with an operating system and keeping that balance with a healthy lifestyle, exercise, sleep, lowering stress, and eating the right foods and staying away from the wrong foods actually allow us to make this entire life journey our lifespan, from a baby two days old, again, over to 90 plus years old, and I know you spent a lot of time with the 90 plus year olds when you're in the blue zones, they have healthy metabolisms that is in part really shaped and groomed and care taken by their lifestyle, including their diet.

Dr. Mark Hyman:
It's so true. So you think it is a problem if we're overweight and you don't think it's healthy at any weight based on what you're seeing.

Dr. William Li:
I think overweight and underweight, both ends of that spectrum are not healthy. What we want to do is kind of get towards the middle, and the middle actually has, by the way, probably a pretty big, it's not a black or white. It's not a thin line. You cross that line, you're overweight and you're unhealthy. I think there's a band of really where there's a zone that's very individual. We talk so much about personalized medicine, individualized care. I think that for every individual at different parts of their life, there's a cycle in which you can actually go up and down a little bit and you're probably going to be just fine. But if you exceed the highway and think about it, one-lane highway versus a two-lane highway versus a four-lane highway, you can still go off road. You can still go off the edges on either side and get into trouble.
And I think that every individual's got a different kind of size of highway be based on who they are and also at different points in their life. We're at this new juncture of understanding our metabolism. And the wonderful thing to me is that number one, our metabolism is not our fate. We are not born to suffer a bad metabolism. There's something we can do about it, which is actually we can help our metabolism shine, we can help our metabolism rise, and we can take steps including using food to beat the need to have these extreme diets that actually wind up being unsustainable anyway.

Dr. Mark Hyman:
So then how do people best lose weight and lose their body fat? And what is your sort of prescription and sort of the Eat to Beat diet?

Dr. William Li:
Yeah.

Dr. Mark Hyman:
Do we take all this science and make it practical? Let's like take the last 10, 15 minutes and make it real for people.

Dr. William Li:
Yeah. Well look, I get asked this question all the time. When people see me wherever on the street or in an lecture hall, they basically say, Dr. Li, what diet do you follow? Right? Because they're assuming we all follow our own, a special diet or our own diet. And I answer very, very, very authentically, very sincerely. I'm not on a diet, I don't go on a diet. However, I do eat in a certain way. And the way that I eat, and I think people will relate to this, I call it mediterrasian style of eating. Mediterrasian happens to reflect the ways that I like to eat, I enjoy eating, and reflects my own background. I'm Asian. I grew up eating Asian food. I lived in the Mediterranean and I spent time in Italy and in Greece and elsewhere, and I lived Mediterranean. I lived and learned to love Mediterranean cuisine, especially traditional cuisine.
So I always, whenever I'm choosing a meal or ordering off a menu or going shopping in a grocery store or the farmer's market, I naturally gravitate towards recipes and ingredients from one of those genres, which by the way, Mediterranean, Asian happened to be traditionally among the healthiest eating patterns on the planet.

Dr. Mark Hyman:
Yeah, yeah. Well, the blue zones are in Okinawa and basically the Mediterranean places, right?

Dr. William Li:
Exactly. Right. So I mean, you were just there seeing this in action. And so I call it mediterrasian style eating. And I think that I use that to inform what ingredients I pick, what catches my eye, how foods are prepared. And by the way, also Mediterranean and traditional Asian foods, I think of these culinary traditions, tend not to be ultra processed. They tend to use fresh, local seasonal ingredients combined in really unique ways, and flavored with herbs and spices and nuts and legumes and healthy oils like olive oil. So that's one approach I take is how do I, for anybody's sort of confused, okay, well what style of eating should I-

Dr. Mark Hyman:
What's Mediterrasian, but Mediterranean can be anything. It can be like pasta and pizza, or it could be fresh fish and vegetables.

Dr. William Li:
So that's really what I try to do is I try to present people with a list of ingredients you can buy in my book, in the grocery store, in the produce section, in the middle aisle, whether you're going to the seafood counter or you're go into the farmer's market, you can find these ingredients and they taste delicious. And you have to, somebody who said, I haven't had broccoli, or I don't like fish, you haven't had somebody prepared for you in the right way.

Dr. Mark Hyman:
That's my theory. I think the reason people don't like vegetables is they were prepared poorly. I remember I was in the movie Fed Up and I went down and this family who basically never ate vegetables and thought they tasted bad because mostly they came out of can and were awful, right? Or overcooked or mushy.

Dr. William Li:
I hope you whipped them up some.

Dr. Mark Hyman:
I did. But you know what this woman said? She, she's had a friend of hers make her asparagus on the grill and she thought, oh my God, this is really good.

Dr. William Li:
Exactly. And that's by the way, where I think if you see an ingredient that can activate your brown fat and help your metabolism and you don't know how to cook it, in this day and age, go onto Google or if you're shopping for it, go onto Google, type the ingredient type, Mediterranean or Asian and type recipe and then search video. And somebody will come up to show you-

Dr. Mark Hyman:
Oh, for sure.

Dr. William Li:
With passion, how to do it. That's a great simple way to learn how to cook these ingredients. But it's not just ingredients mean. So basically fruits and vegetables, nuts and legumes, all the usual cast of characters. And I try to identify specific ones. The middle aisle, dried fruits and dried fruits and dried mushrooms, dried chili peppers, dried beans, all great candidates as well. Capers, I really love. Seafood, I take people into the seafood section.

Dr. Mark Hyman:
Why are capers so good?

Dr. William Li:
Oh, okay. Do you know that in onions, okay, which are not related to capers. You go to the produce section, you see onions, they've got quercetin. Quercetin is a natural bioactive that activates your brown fat. It actually redirects your white fat. It causes beigeing to your white fat, harmful fat. Starts to look a little bit more brown, starts to do the right thing. And also redirects the stem cells so you make less white fat and more brown fat. But quercetin in an onion is found 66 times higher in a caper.

Dr. Mark Hyman:
Oh wow. Because I love capers.

Dr. William Li:
I love capers too.

Dr. Mark Hyman:
And by the way, for those of you listening, you've been checking in on my podcast, you heard me talk about quercetin for longevity, and it's one of the compounds, it's super important that actually can help reverse biological age. So I think it's very, very key.

Dr. William Li:
And where do you get quercetin? You get them in dry, rocky Mediterranean islands, and capers are actually flower buds that are picked before they turn and open up as flowers and they're packed in salt or they're packed in brine or a little vinegar and you know, got to rinse off all that extra salt. But whatever you are eating that's savory, if you add some capers to it, anything-

Dr. Mark Hyman:
Oh it's so good.

Dr. William Li:
It will make it taste so much better. Yeah. And if you haven't been exposed to capers, you got to try it. Capers from the island of Santorini or capers from the Sicilian island of Pantelleria, those are some of the most famous culinary capers that are out there. I like to cook. I mean, I know you do as well, but I think that the other thing is really talk to somebody who really enjoys cooking about these ingredients. And you'll get excited about them as well.
But the point is that you can go to the seafood section. Something I wanted to tell you that I discovered, so when I was writing the book, some of the people advised me said that you know Dr. Li, that a lot of people don't like to eat seafood, so be careful including fish in your book. And that made me want to really write about a whole chapter on seafood. I call it the daily catch. And the reason is this, if you've ever lived near the shore, if you've ever been to Asia or the Mediterranean, there is so much tasty seafood there. And here, I think in most, like in America, most places go ah, salmon, the salmon or the chicken. I'll take the chicken at the wedding or whatever. It turns out that yes, oily fish are healthy because you get marine omega-3 fatty acids. But there was a study from Iceland that was quite surprising. They wanted to look at what the effect of omega-3 fatty acids were on body fat. And guess what? Turns out brown fat helps you lose weight, burns away visceral fat so your waist size can shrink. And of course they found it that eating salmon three times a week for eight weeks will actually cause you to lose up to 15 pounds. All right, so that's a lot weight.

Dr. Mark Hyman:
Wow.

Dr. William Li:
Yeah.

Dr. Mark Hyman:
Wait, wait. So you said eating salmon a few times a week-

Dr. William Li:
Three times a week.

Dr. Mark Hyman:
Can help you lose 15 pounds?

Dr. William Li:
Over eight weeks, yeah, so basically now this is the study where they actually did a little bit of caloric restriction to get it started. Then added salmon to see if eating salmon would actually trigger faster weight loss. So that's a pretty good amount of weight loss. Now omega-3s are in salmon, right? That's an oily fish, in fact, I can tell you there's 1500, 1,565 milligrams of marine omega-3 fatty acids in a five ounce serving of salmon. But here's what's crazy, and I think this is what opened my eye. The same researchers studied what they thought was going to be a non oily fish like cod, cod's not considered an oily fish. COD only has 284 milligrams, not 1500 of omega-3 fatty acids pretty low. Guess what? They found people that ate cod three times a week, lost 10 pounds over eight weeks.

Dr. Mark Hyman:
Wow.

Dr. William Li:
Three times a week.

Dr. Mark Hyman:
Was it because of what they were not eating or was it because of the fish you think?

Dr. William Li:
Both. Because basically when they lowered their calorie intake, that kick started it. But when you compare cod with salmon, you lost 10 pounds with cod over eight weeks. You lost 15 pounds, 30% more if you had salmon. But guess what? Cod has so much less of the omega-3s. All right, so we're comparing, we're just comparing two kinds of seafood here. So you don't need as much omega-3 as we thought. You don't have to eat mackerel and anchovies in order to get adequate omega-3s. When it comes to your metabolism to fight fat, something as low as cod with that amount of omega-3s will do it.
So in my chapter, I convert in different seafoods, that cod amount of omega-3s. You want 294 milligrams of omega-3s in a serving. Guess what? That translates to medium size gulf shrimp. Oh, you only need eat four gulf shrimp to get as much you get in a serving cod. How many oysters? You need to eat eight oysters. You want mackerel, which is really oily, you only need one forkful of macro to get that amount as cod. You don't even need that much mackerel. Open up a tin, just take one fork full and you're done.

Dr. Mark Hyman:
That's amazing.

Dr. William Li:
Halibut, another white fish-

Dr. Mark Hyman:
You can even plug your nose.

Dr. William Li:
Halibut, which is a very mild white fish, right? Not oily. You only need to have eat half a piece of halibut, half the size of a deck cards in order to get the same amount of omega-3s as you get in cod. So what I do, I go through all kinds of spiny lobster, mitten crab, razor clams, like stuff that I love to eat.

Dr. Mark Hyman:
Yeah. Oh, I love razor clams.

Dr. William Li:
So I'm telling you, so you got to check out this chapter eight. It's called the Daily Catch. And I have a complete list with all the converted doses of how much many you need to eat. Joe Stone Crab kind of thing, like stone crab. How many claws would you need to have? It's all there. So look, eating for your metabolism and to fight body fat doesn't have to be a chore. Don't fear your food. Love your food.
Look at all the stuff that comes from the Mediterranean and from Asia. Look at the recipes. You got to be careful what you eat. But then the last part of it, by the way, of how I do this, just to share a practical way besides what to eat and how, and be careful not to overload your fuel tanks by overeating. There is really quite a profound aspect of metabolism, body fat, and fat burning when it comes to intermittent fasting. So everyone thinks that intermittent fasting is, it's like modern trend, but it turns out that we're always intermittent fasting when we're sleeping, we're not eating, we're fasting. When we get up in the morning, eat breakfast, we're breaking our fast, which is why we call it breakfast.

Dr. Mark Hyman:
Or should be.

Dr. William Li:
Now remember I told you, right, remember what I told you? When you actually eat food, your insulin rises in order to draw that energy to load into your cells. Our metabolism's hardwired so that when you're eating with and your insulin's going up, our metabolism stays focused on loading up on fuel and not burning it. Okay? When we're not eating, our insulin goes down, our metabolism switches gears like switching train tracks and basically says, all right, it's time to burn some of that fat stored in cells. And maybe you're burning the fat from dinner, maybe you're burning the fat from yesterday. Maybe you're the burning the fat from the holidays, but that's actually when you're sleeping, you're actually able to burn. That's the way our metabolism is hardwired. So here's what I do. I try to give my body as much time to naturally burn fat as possible. If I'm sleeping eight hours a day from 11 o'clock to seven o'clock, for example, all right, here's what I do.
When I eat dinner the night before, if I eat dinner at seven o'clock and I put the dishes away at eight, I don't eat anything after dinner. I've stopped. I closed my eating window at eight o'clock.

Dr. Mark Hyman:
Yeah, everybody should do that.

Dr. William Li:
No midnight snacking. No noshing. I don't raid the fridge. No extra slice of pie before I go to bed. Now guess what? I put the dishes away at eight o'clock, I go to bed at 11, I've gained three extra hours of fat burning, metabolism grooming. When I get up in the morning, I don't do what our moms told us to do, which is hurry up and eat breakfast and catch the school bus to go to school. I get up, I take a shower, I get dressed, I take my time, I go for a walk or I'll check my email or do something else. I'll wait an extra hour before I eat breakfast. Okay? Now I've gained an extra hour. So the eight hours of sleep plus the three hours the night before, 11 hours plus one extra hour in the morning. I have just spent half my day burning down extra fuel. Super easy. You want to go intense? You want to go 16 hours and squeeze down eight, go for it. But 12 hours works as well. I'm just trying to tell people easy, practical, delicious ways to do it. And then if you want to go hardcore, go for it.

Dr. Mark Hyman:
Well, William, your book is just so chockfull of all sorts of practical tips as well as all the science behind it and the why, which I think help people change their biology. And you talk about how phytochemicals influences, how the microbiome influences how your fat affects your brain health and cancer risk, and so much more, how to shop and like to drink. I mean, your book is just really quite beautiful and deep and richly researched. So I encourage everybody to get a copy. It's called Eat to Beat Your Diet: Burn Fat, Heal Your Metabolism, and Live Longer.
William, you're a good friend. You're brilliant, man. You're awesome and you love food like I do. And we're actually going to be on a panel at a conference in a couple of days to talk about Food is Medicine. So the whole healthcare system, which I think it's news to, but it's not news to us or news to all of you listening, and thank you so much for listening to Doctors' Farmacy. Thank you, William, for being on the podcast. And if you love this podcast, please share it with your friends and family on social media. We'd love to have them learn about all the things that you now know about. Leave a comment, how have you hacked your metabolism? And what have you learned about how it works and what you've done to actually improve your metabolism? And subscribe wherever you get your podcast and we'll see you next week on The Doctor's Farmacy.
Closing:
Hi everyone. I hope you enjoyed this week's episode. Just a reminder that this podcast is for educational purposes only. This podcast is not a substitute for professional care by a doctor or other qualified medical professional. This podcast is provided on the understanding that it does not constitute medical or other professional advice or services. If you're looking for help in your journey, seek out a qualified medical practitioner. If you're looking for a functional medicine practitioner, you can visit ifm.org and search their find a practitioner database. It's important that you have someone in your corner who's trained, who's a licensed healthcare practitioner, and can help you make changes, especially when it comes to your health.