Dr Rupy: William, thank you so much for coming back on the podcast. It's a pleasure to be here with you, albeit virtually. The last time we met was at the conference last year and hopefully I get a chance to see you again this year.
Dr William Li: It was such a great opportunity for us to get together in person and thank you Rupy for inviting me.
Dr Rupy: Of course, man. I was thinking about where to start our conversation today, given that we've had so many really good chats in the past. I'm reading your your latest book. I was fascinated by how Bruce Lee has influenced you, you know, as a sort of like a childhood hero of yours. And I wanted to dive into into that and and what we can learn from Bruce Lee about the way we approach nutrition and healthy eating. I thought it was just a wonderful section of the latest book.
Dr William Li: It's so wonderful that you jumped right to that deeper section in my new book, Eat to Beat Your Diet. I write in this book about the new science of metabolism. I take people on a tour of the supermarket, the grocery store, to look for all the foods that can actually activate your metabolism, fight body fat and elevate your health. But at the end of the day, I think what readers really want is to feel there's some clarity on how do you put all this information together in your life. Being that we are all different individuals. You know, nutrition, they talk about personalized and precision nutrition as a sort of a tech forward field. But really personalized nutrition is something that is very natural to us. When we learn to eat solid food and we are out in as school kids wandering around the school cafeteria, a little extra lunch money, you sneak down to the the deli or the drugstore or whatever to buy your snacks. Look, we all make choices that are personal to ourselves. And I think that when it comes to food and health, as a scientist and as a doctor, I'm all about sort of not being fooled by just there's a superfood. It's really the body that's kind of super. And when it comes to food and health, it's not just about the food, it's about how our body responds to what we put into it. But in this book, I actually really address something much more deep that partners with the food, how your body responds, which is how our mind responds. And it's not just a cognitive act. It really is sort of an act of identity. And this idea that Bruce Lee brought forward. Now look, anybody who doesn't know Bruce Lee, just by a quick introduction, he's a guy who was an American, born in San Francisco, who grew up in Hong Kong because his father was an opera star, and came back to America in his late teens and early 20s for college. And he became and he brought with him martial arts, specifically Chinese kung fu. And as he was trying to teach Chinese martial arts in the late 1960s and early 1970s to a very polarized and and somewhat racist environment in the United States, he realised that there was this wonderful melting pot of different individuals with different body sizes, different body shapes, men and women, athletes, non-athletes, and and people with different physical capabilities that made America really what it is, and this melting pot. And he realised that the rigidity of the martial arts that he was trained on, which was a style called Wing Chun, actually wasn't going to be allow everyone to adapt and adopt and learn how to actually use their body to the fullest. And so this idea that he came around that you should learn the tools and you should learn as many skills as you can, but to master an art, you have to really make it your own. And in making it your own, you want to sort of don't get stuck on the rigidity of practices that other people say you must do, but you need to understand yourself first. And that self-knowledge allows you to adapt your individuality to the circumstances and situations at hand, using your own skills to be able to master your environment and and to thrive. Okay, so that led to an entirely new style of martial arts called Jeet Kune Do, which exists to this day. And Bruce Lee single-handedly transformed the entire world, the entire planet of martial arts. And in fact, people say that he he was the pioneer of mixed martial arts, which is actually one of the, you know, very popular ways to have have combat and in a competitive and sports setting now. So how does that relate to diet nutrition? Well, on one hand, you know, for my perspective, I grew up with Bruce Lee being an influence to me. For me, it was what inspired me about him was like, I mean, this dude, man, he was metabolically fit. He was, he was like cut. Anybody who sees him today, like he's still picture perfect. His body looked like you drew him out of a comic book. But what was really and but you know, as I as I became an adult, what I realised is that the philosophies of his art and his craft really make so much sense in other parts of my life, which is when and so so how does that Bruce Lee chapter actually fit into how to eat to beat your diet? How do you activate your metabolism? How do you actually elevate yourself to a better health is is look, there's some principles of how our body work. But unlike diets, strict rigid diets, which are based on elimination, restriction, deprivation, my approach is really about leaning into choice, specifically respecting what traditional healthy cuisines of the Mediterranean, in Asia, in particular, and I I I I talk about how I actually eat. It's not a diet, it's a way of eating. It's a style of eating, and I call it Mediter-Asian. And I wade through my life, you know, kind of looking at and inspired by influences from those traditional cuisines, culinary traditions, to look for foods that fit within my practice. However, every day is different for me. I've got a different schedule. If I'm travelling, if I'm working, no matter what my location is, I may have different access to different types of food. So rather than pack my lunch in a box and take my my diet kit with me everywhere. I mean, sound familiar, like for those strict diets, I actually develop a way where I can, knowing myself and my preferences and understanding the principles, I can navigate my life in that Bruce Lee style where I can take the best of what I know, I can reject what's not useful to me in any given situation, and I can look at the the situation at hand and and make quick decisions that will actually allow me to thrive in that moment. And that, that kind of decision making, that choice, that adaptivity, that confirmation to who you are as an identity, I, you know, really believe that in addition to the knowledge about food, the knowledge about your body, is this sort of knowledge about who you are and your relationship with food and being versatile and flexible and adaptive to be able to fit the situation that you're in.
Dr Rupy: Yeah, yeah. I I love that. I've never really thought about Bruce Lee in the context of navigating a quite a complex nutrition world. And I love the the way another parallel is, you know, there were lots of heated debates about which fighting style was the best or superior. And, you know, you say in the book, like he viewed that as as, you know, parochial and self-limiting. Really, you want to learn from the best and adapt it to what you feel suits you best. And and so, you know, when when you navigate a nutrition world, there are these heated debates about whether you should go vegan, whether you should go paleo, whether you should go carnivore, whatever, whatever. But really it comes down to the individual, where they are, what's convenient for them and helping them navigate what is a quite complicated food landscape as well.
Dr William Li: Yeah, choose what works for you, reject everything else and and navigate forward. And you know, and by the way, just like different traditions of martial arts and fighting styles, there are real benefits and real advantages to individual aspects of each one. And and I think that, look, being vegetarian is very healthy because you're eating mostly plant-based foods. Being vegan is an ethical choice, which also makes sense as we have a broader conscience for our planet. But it doesn't mean that you have to be a slave to that, unless you really choose to be. Meat is actually a quite a good source of protein and some micronutrients like iron. But having a carnivore diet, you know, that's not really regarded by science. I mean, the the data doesn't support that as a healthy lifestyle. Um and you know, and eating fish, uh you know, there are concerns about sustainability, there are concerns about heavy metals. Um but you know, there are lots of good things that we're discovering about seafood that actually all work. And so this idea that must eat only plants, you know, or must eat only raw, or must eat only meat, or must eat only fat. These are very, um I say, well-intentioned styles of nutrition in the same way that Bruce Lee looked at all these fighting styles as each having their own kind of um value within their own silos. But that doesn't mean that that's the best way, the most adaptive way to move forward. So take the best, reject everything else, and then and and just keep moving forward.
Dr Rupy: Yeah, absolutely. Um I totally agree. Uh let let's get into the the weeds with uh the new book. So, you know, the previous book, Eat to Beat Disease, you know, was really well regarded. It's helped a ton of, you know, millions of people navigate um the grocery aisles. And this one, you're turning your attention specifically to the science of well-being, metabolism and and and weight. Um before we get into the individual foods, which I think people know and love you about, let's let's dive into fat and and sort of anchor people as to what we mean by fat, what the different types of fat are, where we put it on, and we can go into sort of, you know, uh what what we've initially thought of as fat as an innocuous organ that just sort of sits on top of our organs and actually something that's quite active and, you know, is an organ in itself.
Dr William Li: Yeah, no, I'm glad you asked that. Look, um I want to give a little bit of of uh understanding for people for listeners like, how did I come to write, you know, this book, Eat to Beat Your Diet? All right. Um when I wrote my first book, Eat to Beat Disease, I was really fascinated not just by, not only by the foods that are out there and the new research of food as medicine, but I was every bit as fascinated how the body responds in healthful ways to what we feed it. And our health defenses, which is what I wrote about in my first book, um really is where the action is. You know, how our body naturally can be fed and activated, raise our shields to be healthier. So when, you know, the the success of the first book gave me the privilege, you know, my publisher invited me to actually write another book. And I was really trying to think about what I wanted to write about because I'm a researcher and and I'm in the middle of um streams of data and new discoveries every single day uh that is, you know, almost overwhelming, but thrilling for me as a scientist and a doctor. Um but it doesn't mean I have to write a book about it, you know? This is what I do for a living. And uh my publisher suggested first, why don't you write a diet book? Because, you know, that's what people do, you know, after their follow-up books. And I have to tell you, I had a very visceral reaction to that. And I said, absolutely not. I will not write a diet book. All right? Because diets are um uh I really don't like fad diets and trend diets and extreme diets and pop diets, anything that, you know, kind of like sells to the, plays to the public desire for a magic bullet to be able to shed pounds, you know, fit into a beach, look like a in a bikini, uh and and look better like the, you know, I'm like, look, I'm a scientist and I'm a doctor. I'm really about true health, inner health, and not about vanity. I'm really about sustained um uh uh science-based ways to uh uh flesh out our own health and to and activate it. I don't have a problem with with vanity. I don't have a problem like if you feel better by looking better, go for it. But I did not want to write a book about um about a diet book. And yet, I wrote a book that has the title diet on the cover. And and the key thing is that this is a trick title, eat to beat your diet. It's actually not a diet book, it's an anti-diet book. And the reason it's an anti-diet book is really, as I was doing my own research on metabolism, taking my own research to the next level, I started to see a series of breakthrough research discoveries that really helped to understand that, oh my gosh, the next level of health is really about improving our metabolism. And while most people think they know something about metabolism, they connected to body fat. And what most people think about body fat is quite inaccurate and quite limited. And so I need to explain the science of body fat. And only then can you really break through the clouds to discover this joyous, new, delicious world of how we can actually eat to improve our metabolism, eat to fight body fat. I mean, it almost seems like a contradiction of terms, right? You would eat to fight fat. Absolutely, actively our body can do that. So, let me start by talking a little bit about um some of the myths about body fat. I'm sure, even though you and I are, you know, uh average sized, normally sized, maybe a little slender people, that the reality is is that all of us have stepped out of the shower in the morning, uh looked into the out of the corner of eye and looked in the mirror and seen a little lump or a bump that, you know, we didn't see before, we didn't want to be there. And immediately, you start thinking, hey, that's body fat. And you have a negative feeling about it. And then you step on the scale and if that number isn't what you expect, you're disappointed. And so from the get-go, most of us as adults um have a similar type of experience where the idea of body fat is very much associated with negativity. And in fact, even if you go to the grocery store and you walk by the butcher counter and you see, you know, some of the the meat and you see a rind of fat around it, like that visually just sparks this negative impression, right? Well, I have some news that I uh for for people and I and I write about this in the book, everything we thought about body fat is only partially right. And in fact, the key thing about body fat, the science of body fat is fascinating. Our body fat is not an enemy. In fact, it's a friend. And uh and in fact, we need our body fat profoundly. Our body fat is in fact an organ in our body. We now recognize fat as one of our bonafide organs like our kidney, our pancreas, our liver, our spleen, our heart. And the multi the multiple job descriptions that our body fat wears actually helps to keep us alive and our fat, in fact, allows us to have energy. Our metabolism is predicated, is critically dependent upon the health of our fat. So that's the first thing, like the first tie up that I want to actually say is that, you know, without fat, we wouldn't have a metabolism. And here's something that I think a lot of people won't know, um Rupy, which is that I, you know, as a scientist, we scientists like to understand um a subject by going back to its origins. Where did this come from? What does it all mean? And remember I told you about like the the the the reflection in the in the mirror, I step out of a shower as an adult. But hey, guess what? It turns out that the origin of body fat starts in the womb. Our fat formed when we were in our mom's womb. So when our mom's egg met our dad's sperm and we were this ball of cells that were becoming the future us, the first tissue that got laid down was our circulation because every organ needs a blood flow, a blood supply. Second tissue gets laid down is a whole network of nerves because every organ needs electrical signals that will instruct them on what to do. And the third tissue that gets laid down are tiny little fat cells. And these little fat cells are actually fuel tanks for our future body. Fuel tanks, meaning they store energy so that we can they can power up our body. And how they form when we're in the womb is they form around blood vessels. These little flat fat cells form around blood vessels like bubble wrap. You know the bubble wrap you wrap your candlesticks and champagne glasses in? That's what they look like in the womb. Fast forward, all the organs develop, we have more body fat. Um we get born at nine months, right? And so, um fat is not unhealthy there. Fat is perfectly lovingly, deliciously, beautiful because what do we see when we see a healthy baby that makes us smile? Big, chubby baby. Big tubby belly, big fat cheeks, arms and legs that are like balloons. You know, the clown twists the balloons into a poodle at the circus. All right? That's fat actually is something that makes us feel wonderful when we see a baby, right? Um and imagine this, if you saw a newborn that had chiselled cheeks like a fashion model, long thin arms, long thin thighs, runway style, it would be repulsive. We would go, oh man, there is something seriously wrong with that baby. And you'd be right if you thought that. So the question is, what does fat do? Why do why is fat so important? And why did fat form before we even had a face we could stuff with food? That's a profound question for people who have been struggling with body fat um to really contemplate. And I and I sort of put it out there in a book like, let's rethink body fat. So, there's a couple of new roles that people need to know about body fat. First, body fat is not just insulation, like it's not blubber on a whale. Our body fat actually is a cushion. A lot of people don't realise this, but if we didn't have any body fat and we tripped on the rug and fell on the floor and went splat, our organs would would shatter. So thank goodness we actually have some cushion. Um second, our uh body fat is a an organ, and not just any organ, but an endocrine organ. What does endocrine mean? It means that this is an organ that secretes hormones. We now know our body fat, healthy body fat in a baby, uh in an adult, the normal levels, actually secrete hormones that are critical for our metabolism. Unbelievable, right? Like fat makes we need fat for metabolism? Absolutely. And here's what it does. There's 13 hormones that are known, probably many more we haven't discovered yet. One of them, some people may have heard of, it's called leptin, L E P T I N. Leptin, now some people think of that as a satiety hormone. It turns off your appetite. I want to kind of explain leptin as more as a volume switch on your radio. When you want less appetite, the leptin switch can turn it down. When you want more appetite, your leptin switch can go up. And what does appetite mean? Appetite means that we actually sit down to eat more food, which is our fuel in our body. All right? So leptin is one of those fat hormones that controls our brain and our behaviour and it actually adjusts our appetite so we have enough energy, we can make sure we have enough energy to function. Second hormone, and and you know, we know this Rupy having, you know, gone to medical school, um but I'm sure a lot of people don't know this, but if we were to draw a vial of blood from any individual and send it to the hospital lab and ask the lab to um uh to measure the level of hormones in that tube of blood, testosterone, thyroid hormone, cortisol, um and here's here's one called adiponectin. Adiponectin, the the word, the root comes from adipose, adipose is body fat. Adiponectin is another hormone made by by body fat, naturally. But the key thing about the hormone adiponectin is that when the lab results come back from from your level of adiponectin, it is 1,000 times higher than any other hormone circulating your blood. Holy cow, why is it so high? Because it turns out that adiponectin is the hormone made by our body fat that allows insulin to draw energy from our blood into our cells, right? So when adiponectin is high and regulated, our insulin goes, all right, time to get in that energy, time to draw in that energy and load it up to our cells so we can run the engine of our body. When adiponectin is low, it's harder for it. So you want to have um good levels of adiponectin. So that's the second hormone. Um and if adiponectin is the gas pedal, the accelerator of drawing in energy of your body, and I like to use the analogy of cars because people understand that. A third hormone that is made by fat is called resistin. Resistin resists adiponectin. Resistin is the brake. If adiponectin is the accelerator, the gas pedal, resistin is the brake. So adiponectin goes, all right, let's draw in lots of energy. Resistin goes, not so fast, guys, a little bit slower, a little bit slower. So this kind of is the the foot brake, uh the the gas and the brake pedal that allows our body to drive its metabolism. So, this is all made by body fat, which is pretty amazing. Now, that's the second hormonal thing. The third thing that fat does, um as I mentioned it, it acts as a fuel cell, a fuel tank. So, if you had a car, um and you were driving a car that uses petrol still, um gasoline in America, um uh uh what do you do? You get in your car and you you don't even think about your car and and how the engine is driving, but what you do know, you pay attention to the fuel tank. When the fuel gauge runs low, you know that the engine's going to need some more gas. So what do you do? You pull over to the filling station, you take out the nozzle and you put it into the tank and you fill it up. And when it's filled up, it clicks and it stops filling gas. All right? Um and then you just drive on. You don't even think about it. Well, our body, our metabolism runs very similarly where we need fuel to be able to run the engine of our body. I mean, people listening to this, if you're blinking, if you're breathing, it takes energy. That energy uh uh is is our needs our is powered by our metabolism. And when our fuel tank runs low, our brain, the fuel tank in our brain senses that, when the fuel gauge runs low, what do we do? We don't pull over to the filling station, we pull over to the dinner table or to the restaurant or to the refrigerator or to the pantry to fill up because the food, the the our metabolism, the engine of our body runs on fuel. That fuel that we get as humans is food. Okay, people call it calories. I don't want people to focus on calories in, calories out, counting calories. I want to use the analogy of fuel because that's the important concept. And so when we sit down to eat, we eat something to fill up our tank. All right? The insulin in our body that's released from our pancreas helps to draw that energy from the food into our cells. Anything extra gets stored in our fuel tank, right? Just like a car. The fuel tanks for our energy are fat cells. Remember I told you the bubble wrap that forms when our birth? Those are just fuel tanks. And the fuel tanks start really tiny and depending on how much fuel you're loading up with, they get bigger and bigger and bigger. So a fat cell can expand 100 times its size when you're loading up with fuel. And for those of us who eat mindfully and we stop eating before we're stuffed, um there's, you know, pretty much your body efficiently stores that fuel tank and then you can drive off. Now, imagine what happens if you're filling up your car at the filling station and there's no clicker that stops fuel from going into your tank. The tank fills up, the fuel spills out the side, runs down the side of the car, around the wheels, pools around your shoes. Now you are standing in this overflowed fill in a toxic, highly flammable, very dangerous mess. Go to the food section. Our body doesn't have a clicker to stop fuel from going in. So the more we eat and the more we overeat, we have more fuel. Our body, the cup overfloweth, our fuel tank overfloweth. And so our body goes, oh, wait a minute, your your fuel tank is full now. What does it have to do? Keep on filling up fuel tanks. And when you run out of fuel tanks, out of fat cells, the body says, you know, we still got a lot of fuel, guys. Let's go ahead and make some more fuel tanks. Creates another fat cell from our stem cells, fills that one up. Oh, still not enough. Makes another fat cell, fills that up. And now you can kind of see how overeating gives us more fuel than we need and and then it starts to blow up our body fat. So, but normal levels of eating, this is actually part a very important part of fuel tank. Now, back to the car for one second, Rupy. Um when you, you know, when you have a car, you know that you want to have your car running as well as possible for as long as possible, right? Take care of good care of your car. One of the principles of actually managing the care of your car is to give it good quality fuel. If you give it good quality fuel, the engine will run longer. Same thing for our body. The higher the quality fuel that we put into our body to fuel our metabolism, to give our body our our body's engine energy, the longer our engine is going to run. And just like a car, if you throw in some crappy fuel once or twice, no problem. The car is going to run. But please, you have to make sure you get it back to good high quality fuel. For our bodies, same thing. If you actually um uh eat some poor quality stuff every now and then, it'll bounce back. It's very resilient. But like the car, if you continuously put poor quality fuel into your car or into your body over days, weeks, months, and years, which is what happens in our modern society, what happens is that you know in your car, it's not going to run so well. It's going to break down. The engine is going to be degraded. Same thing as our body. And so this is why this idea of taking care of our metabolism becomes so important and the quality of the fuel I put in there. And then finally, one last thing that body fat does. By the way, this is all amazing stuff of body fat that people don't appreciate. These are healthy, good things of body fat. The other thing about body fat that is a little bit of a hidden secret, by the way, is that, you know, we think of body fat, um our our body fat is a space heater. All right? Now, most people think about fat as wiggly, jiggly, um you know, lumpy, bumpy. Um and and we've got different kinds of body fat. Um the wiggly jiggly stuff under your arm, under your chin, the muffin top around your waist, thighs and butt, all right? Those are the things that people want to get rid of. That's called white fat. Um uh uh there's another kind of white fat. It's it's you can't see it. The jiggly stuff you can see is called subcutaneous, meaning under the skin. There's another kind of white fat that's called visceral fat. Visceral means guts. And so this is fat inside the tube of your body that wraps around your guts. It's normally like packing peanuts in a uh FedEx if you're shipping something, just light lightly feathered in there. It's cushion. Okay? But just like if you're shipping something fragile in a overnight shipping container, if you pack a ton of peanuts in there, really pack them in, you're like, hey, I bought the whole bag of peanuts. I got to use them all. And you keep stuffing in there, okay, like way over packed. You can still force that thin box shut, tape it, and at arm's length, it's still a skinny box, but inside it, it's bursting and it's crushing. And so visceral fat, which is normal, like light lightly, like light peanuts, can actually be turned like a baseball glove that crushes your organs, envelops your organs and crushes them. Very dangerous. And so healthy levels of fat are perfectly fine. They do all these wonderful things like the fuel cell and the cushion. But once you go beyond that, you start to disrupt the organ function, the endocrine function, you start to disrupt, cause inflammation, all kinds of bad things. So even skinny people need to worry about excess harmful body fat. Now, but that's not the that's not a gigantic surprise. I mean, I think people have been talking about that. The real surprise is there's a third kind of fat, and I talk about this in my new book, Eat to Beat Your Diet. It's called brown fat. Now, brown fat is not wiggly jiggly, and it's not under the skin. It's not subcutaneous. You can't even see it. Brown fat is not um it's it's brown fat is paper thin, wafer thin. And it's amazing because it's not near the surface, you cannot see it. It is actually pressed along your neck. It's under your chest. It's under your arms like a bra strap, a little bit behind your back and between your shoulder blades and a little bit in your belly. And this brown fat, by the way, doesn't act it serves a very specific function. It is a fuel cell, a space heater. It generates heat by burning energy. Okay? And I and I give, you know, for the people watching this, I have a little show and tell thing because I I this is why I've been trying to teach people. This is what brown fat is like. This thin paper thin fat. It is like this. This is a torch. When your brown fat is lit, it does this. It actually blows up a flame. All right? This is what brown fat does when you light up the brown fat. And in order to power this flame, it's got to draw energy from someplace. And that energy it draws from, that fuel it draws from in order to create that flame, that heat, is that brown fat, thin fat, pressed down, invisible fat, draws that energy from your dangerous fat, your extra visceral fat and your subcutaneous fat. So here is good fat, brown fat, fighting bad fat when it's in excess. And this is like a completely new conceptualization. And the great news is that there are foods that can activate that brown fat energy burning system.
Dr Rupy: That's fab. I I I've got to commend you. I I haven't I haven't had a description for hyperplasia and hypertrophy of fat uh explained in the way you just did when you go to the petrol station or gas station, you fill up, you know, with the with the tanker because that conceptually made it so much clearer even in my mind and someone who understands, you know, the different ways in which fat grows, you know, via the the cell getting bigger and bigger or the number of cells increasing and how that leads to inflammation. I think that's going to really clarify that process for a lot of people. So that's brilliant. And and again, also the the show and tell with the brown fat, um again, you know, it it's made it a lot clearer, I think in my mind as well, but it will definitely help people understand the benefits of of fat and how we've got fat wrong in a lot of ways. I think most people think of it as the wiggly jiggly stuff like you were saying and you're on your on your um thighs and your buttocks and your arms. Um but it's a lot more to that. And what I was going to ask about actually is um, you know, beyond fat growing through these different mechanisms. How does it relate to another passion of yours, which is angiogenesis? Um and and perhaps we can uh that can be like a bit of a uh a take-off for for diving into the foods that might help uh with with fat.
Dr William Li: Yeah, no, that that's a great question. So remember I told you that fat is an organ, it forms very early in life. And just like every other organ in your body, for fat to remain uh vital and functional for all the purposes that we just described, um it needs a blood supply, right? It's a it's a mass, it needs circulation. And as fat actually gets its circulation naturally, uh when your body needs to make more fuel tanks because it needs to store more energy, and so it makes another fat cell, another fat cell, another fat cell, and you're starting to expand that fat cell. And it's just not not only the number, it's the size. So then you fill it up with the gas tank and now it's bigger and it's bigger and you've got another one that's bigger. Pretty soon, your normal levels of fat. So this is the key point. We all want normal levels of fat. It's very healthy for us, important, very important. Okay? But when you actually have too much fat, excessive fat, it actually becomes harmful because what happens is that as that fat mass grows bigger and it starts to billow, all right? What happens is it grows bigger and faster than the blood supply can support that it naturally has. So it desperately wants to get more blood vessels to grow, which is a process called angiogenesis, which I study, how blood vessels grow to it. And this this excess billowing of fat is where fat and tumors are very similar because tumors also start as small cells, just like a normal fat cell. But as it gets bigger and bigger and bigger, it needs a it outstrips its blood supply. And what happens in both a tumor and in fat when it outstrips the blood supply, because it's just growing too big, the center of the fat or the center of the tumor starts to die. We call it hypoxia, not enough oxygen. It feels like it's getting strangled, not enough oxygen, needs more blood supply, desperately. And too often, the growth outstrips the ability to recruit healthy blood supply. And what happens is that when parts of your an organ starts to die, naturally, is inflammation. Inflammatory cells kind of courses in there like bees coming to a flower bed, all right? And what happens is that those inflammatory um uh cells start to build up. Now, a big um inflammatory mass of fat because you put too much fuel in your body, right? Um like the overloaded tank, the spilled overflowed gas tank in a filling station, the air will evaporate it away. So as you as long as you step away and you let the air evaporate, you'll be fine. In the body, there's no evaporation. You got to burn it somehow and store it. And and and so what happens is that when you're overloaded, it's it's flowing in there. Yes, when it overflows, guess what? Your fat can spill out of the fat out of your your adipose tissue, it can even accumulate in your living and liver and spilled fat energy in our other organs like our liver is poisonous. It poisons, it's toxic to our other organs. So when you grow up bigger, bigger and it spills out and it doesn't have enough blood flow, inflammation starts. And by the way, this inflammatory, toxic environment, this over spilled spillage, you know what it does? It completely damages the normal orchestration of those fat hormones, the leptin, the volume switch, do we want it up or down? Do we want to be hungry or not so hungry? Who knows? The fat's too big, it's too inflamed. Adiponectin that's released to be able to have insulin draw in energy so we have normal levels of metabolism and energy in our cells and insulin works well to, you know, for sensitivity of insulin. I don't know. Do we want it to be more sensitive or less sensitive? Who knows? Let's make a little bit, a little bit of it or less. Screwed up. And now your insulin system is not effective anymore. This is why excess body fat leads to metabolic syndrome. You really sort of throw your blood sugar use off and your insulin off. Third, what about resistin? Do we want more or less uh adiponectin and insulin use? I don't know. It's it's all a mess here. So when you create chaos with this expanded fat mass that tries to grow blood vessels, you get into a problem, big time. Now, the fact that you can actually, the fat wants these blood vessels, if it can't get enough blood vessels, at the very end of the day, not only is it going to start to die, it'll start to shrink back. So, one really interesting analogy to the tumor story, the cancer story is that we know in cancer, which also causes chaos and inflammation and expands and dies in the middle. One thing we know we can do is we can starve cancer by cutting off its blood supply. We can give biotech drugs that can do it. There's been over a dozen approved drugs that are used by oncologists treating cancer patients. I have been involved with developing all of them. Um we also know there are foods that can actually starve cancer. I write about this in my first book, Eat to Beat Disease. Um but guess what? We're now seeing the same principle can apply to body fat. We can eat certain foods that actually are anti-angiogenic, meaning they cut off the blood supply. Look, I know the tumor wants to get more blood vessels to grow bigger, but guess what? If you basically say, no, sir, you are not getting any more blood vessels. That's it. Okay? What happens is that at some point it it just gives up. It's like, all right, I guess we're not going to expand anymore. And so it starts to shrink down. So anti-angiogenic foods actually uh are a way of taming our body fat, the growth of our body fat. And it's not the food themselves. It's not like, you know, the whole, it's not the broccoli, it's not it's not the broccoli that does it or the blueberry that does it. It's the bioactives, the natural chemicals made by mother nature that we've figured out what do those chemicals do in the food to actually thwart the ability for the blood vessels to grow. And by the way, in some cases, the same substances in foods that can tame fat growth by cutting off the blood supply, also can change the ability of the fat to fill up, can help make harmful fat turn into useful brown fat, and can even trigger the the um, you know, the the the brown fat uh uh flame. So you can actually start to burn down fuel and burn down extra fat. So this is really the, you know, the beating heart of my book, which is that, you know, fat is not our enemy. We shouldn't fear fat. We should respect it, but we should tame it. And our metabolism isn't what we're born with. It's not our fate. You know, how often have people heard uh that we're born with a faster or slow metabolism and that's why my sister has a fast metabolism and that's why she's skinny as a stick and never has to worry about what she has to eat. And me, I had a slower metabolism. I've always struggled with my weight and I can't eat everything I want. It's been a big struggle. Well, we now know there's a new science of the metabolism that teaches us otherwise. And we also know now that the link between metabolism and body fat is such that if we were to actually use the hard wiring of our metabolism and how our fat works and make our tame our fat to make it healthy, our metabolism will naturally rise, um uh we will actually lower inflammation in our body, our energy usage will be so much more efficient. And we will start to be uh moving away from the threat of chronic disease. And so that's really the next level of health. You know, wherever you are, wherever you're starting from, if you want to get to that next level, um this is where you start. You start by thinking about your metabolism and reconceptualizing how you think about body fat.
Dr Rupy: Yeah, absolutely. I I think um it'll be a really good uh place to start, I think, talking about the bioactives and food because I I think that's, you know, the body of the book and and and what I found absolutely fascinating about it. But before we get there, you you do touch on how some people are uniquely susceptible to fat uh being uh put on in certain areas. You know, there's a genetic predisposition. Um let's put aside sort of the energy surplus, uh you know, portion control is obviously very important. You also talk about uh a bit of fasting every now and then during the week as well. Um but but what what are the the sort of genetic components as to why someone might be putting on more fat than their their counterparts?
Dr William Li: We're all born different. We all have the same DNA, human DNA, but our DNA is actually put together in different ways. Think about it like a uh a Lego toy. You have every box has the same number of pieces, but how we choose to put them together can be slightly different. All right? Um and and so we all are put together slightly differently and our genetics are put together slightly differently. Depending on how our genes are actually functioning, you could have an extreme where there are some genetic mutations that actually make us exquisitely vulnerable to um accelerated body fat mass. And I I sort of don't want to get too deep into those rare diseases because that's not common and most people don't have them and I'm not encouraging people to go out to get screened for a rare genetic disease for obesity. But but it does exist. Um but other times, you know, we have different gene functions that um influence uh uh our brain sensitivity to leptin, make more leptin, make less leptin, um make uh some sensitivities that also can change our um decision, our cognitive functions in our brain that uh might make us behave more in a addictive personality where, by the way, if you have, I mean, look, addictive personality sounds bad, but in fact, there's another way of there's another definition of it, which is intense focus, right? So we give the reward to somebody who's intensely focused on their work, you know, uh or on their career or on something. But you know, some people wind up getting intensely focused on food, for example. And if you're intensely focused on food, if you have a fixation on your food, it becomes very easy to eat, overeat, and then you've got too much fuel in your body. And so that's another way behaviour can easily overload us as well. And of course, diabetes is a is not a a single disease. It's probably multiple diseases or multiple conditions, genetic conditions that all predispose us in different ways to accumulate too much body fat, to to change, tweak our metabolism, knock our metabolism off off whack. But fundamentally, um all humans start off with the same set of hard wiring, the operating system for our metabolism is the same. It's how we our body uh puts together the Lego blocks in slightly different ways that can influence how we behave and how our body processes the energy that can actually throw us more towards a body fat building um uh mode or not.
Dr Rupy: Yeah, yeah, absolutely. Uh and you know, it always serves as a reminder um to go through those. And as a general heuristic, you know, what what you just described of, you know, if you can't recognize the ingredients, it's packaged, it has a very long shelf life, it most likely has got a lot of contaminants in, a lot of additives. Um the environmental pollutants that you talk about in your book as well about how they're obesogenic, you know, a lot more people are coming around to this idea about phthalates and and other obesogens um as derailing our metabolism. So that's really important. Um I think we should we should go into the good stuff now. Like I I I want to talk about these bioactives. So, you know, it was enlightening to to read about the mechanisms behind bioactives and how they can impact uh healthy fat, you know, how they can amp up uh your your brown fat, how they can trigger thermogenesis and how they can improve your mitochondria, the you know, the the power cells of your the powerhouses of your cells. Why don't we talk about those mechanisms first and then perhaps we can go into some of those bioactives and then dive into some of those delicious foods that you and I both love.
Dr William Li: Sure. Okay. So, um as we discussed, there are um three main types of body fat. The wiggly jigglies, which is the subcutaneous fat you can see, the visceral fat, which is the the choking fat of our organs wrapped around our organs, okay, that you need some of it, but too much of any of those things is not good. And then the brown fat, which is to our to to the best of our knowledge is all good stuff. All right? It actually it's the space heater, the fuel cell, and it's designed to burn down extra energy. So it's a good fat that can fight the bad fat, in fact, by burning off extra fuel. Why, by the way, I want to explain why it's called brown fat because it has to do with the mechanism. Um brown fat is brown coloured and they've looked at this under the microscope because brown fat contains a lot of iron. It turns out that the space heater function, the the the the cellular organelle that generates the heat is the mitochondria. Now, when I was in medical school, and probably you as well, Rupy, and we're trying to we had to memorize everything. Um and there were like thousands of things to memorize every single week. Um I tried to find fun ways to memorize. So I used to I used to memorize mitochondria is the mighty-chondria, you know? And it's small but mighty. And these are the fuel cells. These are the nuclear power plants of our cells. They generate energy. And to generate that energy, there's a lot of iron in it. Same kind of iron that causes rust. All right? That that gets rusty. And so rusty iron is brown. And so mitochondria are brown. And brown fat, even though it's thin and it's wafer thin, is packed with mighty-chondria, this fuel generating, light up um uh stuff, these organelles, the nuclear power plants. And because it's so densely packed with mighty-chondria, mitochondria, it's got a lot of iron in it. So that's why it looks brown. So number one, there's a reason why brown fat looks brown. Okay? Um now, uh the way that actually you can turn on and get rid of harmful body fat, the easiest way is actually to activate thermogenesis. Basically, that's just turning, flipping the switch so that your brown fat starts to fire up. Um I showed you a little lighter, a torch, but actually, if you think about a gas stove, which most people have in their kitchens or their homes, right? What do you do? You turn on the the the handle and it goes click, click, click, click, whoosh, right? That's what certain foods can actually do. When you're eating certain foods, uh it actually sends signals to your brown fat and it goes whoosh. And once it goes whoosh, it it requires, just like your stove, it requires fuel to keep that flame going. Where's it going to draw that fuel from? It's going to draw it from your harmful fat. So that's how you burn it down. So that's one basic mechanism, but it gets much more interesting than that for thermogenesis. For example, hot chili peppers, which I happen to like spicy food, um but everyone knows what happens when you eat something spicy like a chili pepper. Uh pepper flakes you put on your pizza. That's a great example, right? In fact, I have a little sample here. Let me just show you. I just happen to be in front of I just happen to be in front of a desk so I can show you this stuff. Look at that. That's the kind of stuff, right? And it comes like and it comes off of a plant like that. Okay. So what happens is that when you put it on your tongue, you feel the burn, the zing. And what's happening is that there's a bioactive called capsaicin. It actually is also there's a whole family called capsaicinoids. They're all that chemical family. And like a key that fits into a lock, your tongue has the lock. It's a receptor for capsaicin. It's a capsaicin receptor. There's a name for it, by the way. I know I'll be giving lots of easy to understand analogies for for your listeners and viewers, but all right, we got to dive in and be a little bit of a scientist here. That receptor is called Trip V1. And it's not only all over our tongue, but it actually is in our esophagus and our stomach, in our guts, all the way down to our intestines, and it and it's and it's also at the very tail end even in our rectum. So you've heard that saying, burning on the way in and burning on the way out. Hey, you know what? That's because of Trip V1, the receptor. But here's the interesting thing, the connection between body fat and thermogenesis. Hot chili pepper on your tongue, lock, the key fits into the lock, the Trip V1 receptor. As soon as that happens, you feel, ah, it's spicy. Your tongue sends a text message to your brain, amazingly. And it tells your brain to do two things. One is to release endorphins. Endorphins are the feel-good hormones, which is why some people really are addicted to eating spicy food. Ah, I got to have I got to have me some more spicy food. Now, the other thing that and not everybody has the same degree of response. So some people, it's just way too spicy. They're they have too many receptors. They have the Trip V1 is so dense in their tongue that even a little spice is overwhelming. Okay? But the second thing that that the capsaicin from chili peppers on the tongue can activate with a text message to your brain, it can release norepinephrine. Okay? Norepinephrine is a flight or fight hormone. So basically, put up your dukes, all right? Or run away. Okay? And what happens is that and and and what happens when you do that? Your eyes dilate, uh you start to sweat, right? And remember people eating spicy food, they often sweat and they turn red, right? Um you start breathing a little bit faster. That's what's happening. And the next time you eat something spicy, um I think you and I talked about this when we were in person um uh last year, but you know, this is what's amazing. If you eat something spicy and and you just put yourself like meditate a little bit, go into a quiet place and pay attention to your body, you will literally feel your brain, your activated brain, your texted brain releasing norepinephrine. You'll feel it running down the side of your neck because the norepinephrine is going down nerves. You will actually feel that sensation happening, the current going down. And it goes right down to the brown fat that's pressed around the side of your neck to light up that flame. That's called thermogenesis. That um uh that that signal norepinephrine binds to a receptor on the top of your brown fat. It's called UCP1. Don't worry about the names. But what that UCP1 does, another lock and key on top of your brown fat, is it then ignites your um your uh burner on your stove. Uh and then whoosh, it goes up. And now in order to keep that flame going, it's got to draw the energy down, right? So that's an example of chili peppers found in both Mediterranean cuisine, um Asian cuisines, all kinds of Asian cuisines, that actually are part of this um culinary traditions that that, you know, are are very much part of our humanity. And that's just one example of an ingredient and a mechanism. There's other ways mechanisms that can work as well, but I thought I would start with thermogenesis.
Dr Rupy: I love that. Yeah, yeah, absolutely. I mean, you know, I remember talking about that and how uh and the meditation and, you know, being intuitive as to what's going on in your body. Um for for for those of, I mean, there was also a reference to a couple of studies or lots of studies in the book about a dose response with more chilies in the diet. So they looked at different uh a population and they measured how much chili they have in their diet every single day. And you can definitely see a dose response in the uh likelihood of them being uh slim as well. So, you know, it's a a mechanism that nicely fits with some epidemiological data as well that you've, you know, put throughout that entire book.
Dr William Li: And clinical trials because they've actually taken the capsaicin out, capsaicin out from chili peppers, they've packed them into a little um uniform tablet so the same dose and they've studied this, low dose versus high dose and they gave an intervention for four weeks, eight weeks, 12 weeks and you can kind of see the longer you give it, the more weight you will actually lose. And so, you know, by the way, this comes right back to something very important. Um most people who go on diets have a singular goal, which is actually to lose weight. But what we really want to do is improve our body body composition by burning down the harmful fat.
Dr Rupy: Let's let's dive into different categories of food now. Um fruit. I think fruit has got a bit of a bad name, you know, everyone's sort of demonizing the fact that it has uh natural, delicious sugars. Um but you you you know, you talked about apples, grapefruit, berries, uh you know, even tomatoes uh as as being beneficial as part of this smorgasbord of all these different ingredients should be that we should be consuming. What why don't we dive into a fruit of your choice and and and go into what they contain and how they might be beneficial at fighting fat and and and improving our metabolism? Because I I think it's, you know, something I'm commonly asked about, like, should I eat fruit? Is it not, you know, uh is it not something that puts makes me put on weight?
Dr William Li: You obviously you can see I'm I'm in front of a table that's that I've been using for show and tell. Here's one of my favourite fruits. It's a pear. Okay? And it's a medium-sized pear. And pears are very nutrient dense. It's one of my favourite fruits. Um they're sweet, but not too sweet. They're not as sweet as a mango, they're not as sweet as a pineapple. Um and they've got a lot of dietary fibre. They've got six grams of dietary fibre. And pears also have a bioactive called chlorogenic acid. Um chlorogenic acid is not only found in pears, it's found in apples, it's found in coffee. You know, mother nature is very clever. She actually puts a lot of these useful bioactives across multiple food types. But I love pears. And I want to use this um one of the things that I I a fruit I enjoy eating to address this um I think it's a it's an extreme interpretation, well-intentioned, about the harms of sugar and fructose. I think that as as people, we we love to either um make a food a hero or a villain. And um it is true, sugar, too much sugar, not good for you. But you know, our brain depends on sugar. Our body can make sugar. And so it's really not fair to basically say, oh, a sweet fruit is really bad. Um fruits are very nutrient dense, which is they have sugar for energy, they have fibre for our gut microbiome, they've got bioactives to activate our health defenses and activate our metabolism and activate thermogenesis as well. Here's what you want to do. You want to actually choose foods like fruits that have that taste great, that are pleasing, um that also are nutrient dense and give you all these other factors um that that are good for your body. So net net, you're getting some energy from the fructose and the sugar, you're getting some prebiotic stuff from the from the dietary fibre, and you're getting a ton of these bioactives to activate your health defenses. You just can't reduce everything to the sweetness of the fruit. That's ridiculous. I think that it's very important to actually uh uh state that.
Dr Rupy: Yeah, yeah. It's a really good, really good point. I mean, that's why uh when people ask me about it, I think it's one of those things nice to have, not something you should have every day, you know, uh or as a treat. Um not I don't what I love about your sort of philosophy is nothing's off the table, right? You're you're a true foodie. You want people to enjoy the the pleasures of food, but it's just, you know, sometimes these are the things that we have every single day and then there are other things that, you know, we have as as a treat or as a luxury item. Um I want to I want to parlay into uh into vegetables here because I I think particularly at this time, there's a lot of attention being given to weight loss drugs. Um you know, GLP-1 uh uh drugs, uh analogues like semaglutide or you guys, I think have a brand name called Wegovy, I think it's called. Um and I was really interested in the mushroom section. Mushrooms are also very popular right now, you know, for lots of reasons. Some psychedelics, some, you know, the the more sort of rare forms like Lion's Mane and Chaga. But even your regular store cupboard mushrooms are fantastic. Let let's dive into that a bit because it's got multiple attributes, right?
Dr William Li: First of all, I love mushrooms. Uh happens to be one of my favourite foods. This is like, I'm on the Doctor's Kitchen podcast, so I got to talk about my my enjoyment of food and I like to cook like you. You know, there's nothing whenever I go to the market and I see really good mushroom specimens, especially the ones that are seasonal or not that common, I'll buy them right up. They are mother nature's like umami bomb. They taste great, they're easy to cook, and you know, from a from a medical food as medicine perspective, I can tell you they contain um a bioactive called beta-D-glucan. Happens to be a soluble fibre. So this this beta-D-glucan is not only a bioactive that activates your health defenses and activates your metabolism, it's a dietary fibre that feeds our gut microbiome. So mushrooms are good for gut health and overall health and our metabolism at the same time. Now, what's really interesting about um beta-D-glucan is where is it found in the mushroom? Most people who buy mushrooms and cook with mushrooms get the cap. They cut off the stem, throw away the stem. And the cap does have beta-D-glucan, but the stem of the mushroom has twice as much beta-D-glucan. So if you're cutting mushrooms up, cook with the stem or do something else with the stem. You can put it into a smoothie, you can actually make a soup out of it, make a stew out of it, sauté it. Whatever you're going to do, don't throw them away because they actually have a lot of this great natural resource that's good for your health and good for your metabolism. This has been studied, by the way, um in clinical studies where they actually looked at um substituting just, so they took a group of meat eaters. Um these are carnivores, they eat red meat almost every day. And they just asked them to swap out the beef for um the meat for um mushrooms, which is kind of meaty like. Um just two times a week. So these are people that ate meat seven days a week, two days out of the week, eat some mushrooms instead of their meat. So think about it. That's five days of meat eating, two days of mushroom eating. At the end of a year, they actually found that the meat eaters actually gained weight, increased their body fat, their waist size increased. The full meat eaters, just like you expect. But the people who swapped it out for mushrooms just twice a week with something that can be made to taste like meat, actually, um uh put it on the grill, barbecue, put it, you know, sauté them, you can really get a really, really nice unctuous kind of like flavour out of this, umami bomb. They actually shrank their waistline by an inch. They lost by body composition, some of the harmful body fat, the visceral fat. Their blood pressure came down. So mushrooms are really powerful. And by the way, these are culinary mushrooms. You mentioned chagas and lion's mane and cordyceps. One of the things that I like to tell people is that medicinal mushrooms, um we have to be careful about them because they're separate from culinary mushrooms. And although they're very popular these days, you don't want to treat medicinal mushrooms just like you would treat um a culinary mushroom. Culinary mushrooms, what are those? Well, they're all over the place. White button, portobello, cremini, maitake, um porcini, uh uh, you know, um uh enoki mushrooms. I mean, the list goes on, trumpet mushrooms, king trumpets. They don't have medicinal psychotropic or any other immuno, like immuno-influencing properties, the way that certain medicinal mushrooms do. Medicinal mushrooms tend to be very expensive. And there was a reason thousands of dating back thousands of years where healers, traditional healers reserved medicinal mushrooms for specific ailments. And I think that's one of the cautions I want to give is just because they're called mushrooms and just because you can buy them and just because they're not regulated as such, look at the wisdom of the elders. People were not eating chaga mushrooms like they weren't making a chaga mushroom omelette, for example, whereas they would actually make a white button mushroom omelette. Be careful.
Dr Rupy: Yeah, yeah, absolutely. Um, I think it's really important and, you know, when I look at an apple or a pear or a berry, I don't just think about, you know, it's got vitamin C, it's got a bit of sugar in. I'm thinking of like the hundreds if not thousands of different polyphenols that are having unique impacts on my body. Yes, some of it is on uh on on weight control and, you know, all the things I've learned from your books, uh but also, you know, on angiogenesis, on DNA, on our gut microbiota, you're you're really you I want people to really think about the wider aspects of what we're consuming on a day-to-day basis. And whole foods are just fantastic at giving us that that huge selection of of different uh nutrients.
Dr William Li: Now, let me give you an example though where we do want to be careful. Oranges, citrus are wonderfully delicious. They're pretty sweet. Okay, there's quite a lot of sugar in an orange. People always ask me, well, what about fruit juice? And I tell people, you know what, oranges, citruses are are very nutrient dense. They've got dietary fibre. Anybody who's ever peeled an orange and eaten it slice by slice knows there's a lot of dietary fibre to it. You can see it, you can taste it, you can feel it. It's also very sweet, um which, you know, is good, but too much sweetness, not so good. And it's loaded with bioactives, like these polyphenols, naringenin, hesperidin, limonene, like all kinds of great stuff that's good for your metabolism, fights body fat, activates your health defenses. But let's compare an orange to a glass of orange juice. Now, I like to eat, I like, I actually like orange juice. But you know, if you remove all the fibre from an orange, all the pulp, you're getting, you're removing a lot of the good stuff. All right? If you ultra process the orange juice, like you see in a lot of the commercial inexpensive versions you can buy in the grocery store, you might have actually removed some of the polyphenols as well. But even if you fresh squeeze it, a tall glass of orange juice, I could, you know, on a hot day and I want to slake my thirst, that tall glass, that'll go down my gullet. I can whip it down in 30 seconds, glug, glug, glug, glug, right? Okay. You know how many oranges in the sugar of oranges that would take to make a tall glass of orange juice? On average, eight oranges. Now, I would never sit down and eat eight oranges at a time. That's an example of where if you want the the all the beneficial healthful benefits of fruits versus the juice, if you choose the juice, it's a lot easier to eat a lot more of that sugar compared to the whole fruit.
Dr Rupy: Yeah, yeah, it's a really good, really good point. I mean, that's why uh when people ask me about it, I think it's one of those things nice to have, not something you should have every day, you know, uh or as a treat. Um not I don't what I love about your sort of philosophy is nothing's off the table, right? You're you're a true foodie. You want people to enjoy the the pleasures of food, but it's just, you know, sometimes these are the things that we have every single day and then there are other things that, you know, we have as as a treat or as a luxury item. Um I want to I want to parlay into uh into vegetables here because I I think particularly at this time, there's a lot of attention being given to weight loss drugs. Um you know, GLP-1 uh uh drugs, uh analogues like semaglutide or you guys, I think have a brand name called Wegovy, I think it's called. Um and I was really interested in the mushroom section. Mushrooms are also very popular right now, you know, for lots of reasons. Some psychedelics, some, you know, the the more sort of rare forms like Lion's Mane and Chaga. But even your regular store cupboard mushrooms are fantastic. Let let's dive into that a bit because it's got multiple attributes, right?
Dr William Li: First of all, I love mushrooms. Uh happens to be one of my favourite foods. This is like, I'm on the Doctor's Kitchen podcast, so I got to talk about my my enjoyment of food and I like to cook like you. You know, there's nothing whenever I go to the market and I see really good mushroom specimens, especially the ones that are seasonal or not that common, I'll buy them right up. They are mother nature's like umami bomb. They taste great, they're easy to cook, and you know, from a from a medical food as medicine perspective, I can tell you they contain um a bioactive called beta-D-glucan. Happens to be a soluble fibre. So this this beta-D-glucan is not only a bioactive that activates your health defenses and activates your metabolism, it's a dietary fibre that feeds our gut microbiome. So mushrooms are good for gut health and overall health and our metabolism at the same time. Now, what's really interesting about um beta-D-glucan is where is it found in the mushroom? Most people who buy mushrooms and cook with mushrooms get the cap. They cut off the stem, throw away the stem. And the cap does have beta-D-glucan, but the stem of the mushroom has twice as much beta-D-glucan. So if you're cutting mushrooms up, cook with the stem or do something else with the stem. You can put it into a smoothie, you can actually make a soup out of it, make a stew out of it, sauté it. Whatever you're going to do, don't throw them away because they actually have a lot of this great natural resource that's good for your health and good for your metabolism. This has been studied, by the way, um in clinical studies where they actually looked at um substituting just, so they took a group of meat eaters. Um these are carnivores, they eat red meat almost every day. And they just asked them to swap out the beef for um the meat for um mushrooms, which is kind of meaty like. Um just two times a week. So these are people that ate meat seven days a week, two days out of the week, eat some mushrooms instead of their meat. So think about it. That's five days of meat eating, two days of mushroom eating. At the end of a year, they actually found that the meat eaters actually gained weight, increased their body fat, their waist size increased. The full meat eaters, just like you expect. But the people who swapped it out for mushrooms just twice a week with something that can be made to taste like meat, actually, um uh put it on the grill, barbecue, put it, you know, sauté them, you can really get a really, really nice unctuous kind of like flavour out of this, umami bomb. They actually shrank their waistline by an inch. They lost by body composition, some of the harmful body fat, the visceral fat. Their blood pressure came down. So mushrooms are really powerful. And by the way, these are culinary mushrooms. You mentioned chagas and lion's mane and cordyceps. One of the things that I like to tell people is that medicinal mushrooms, um we have to be careful about them because they're separate from culinary mushrooms. And although they're very popular these days, you don't want to treat medicinal mushrooms just like you would treat um a culinary mushroom. Culinary mushrooms, what are those? Well, they're all over the place. White button, portobello, cremini, maitake, um porcini, uh uh, you know, um uh enoki mushrooms. I mean, the list goes on, trumpet mushrooms, king trumpets. They don't have medicinal psychotropic or any other immuno, like immuno-influencing properties, the way that certain medicinal mushrooms do. Medicinal mushrooms tend to be very expensive. And there was a reason thousands of dating back thousands of years where healers, traditional healers reserved medicinal mushrooms for specific ailments. And I think that's one of the cautions I want to give is just because they're called mushrooms and just because you can buy them and just because they're not regulated as such, look at the wisdom of the elders. People were not eating chaga mushrooms like they weren't making a chaga mushroom omelette, for example, whereas they would actually make a white button mushroom omelette. Be careful.
Dr Rupy: Yeah, yeah, absolutely. Um, I think it's really important and, you know, when I look at an apple or a pear or a berry, I don't just think about, you know, it's got vitamin C, it's got a bit of sugar in. I'm thinking of like the hundreds if not thousands of different polyphenols that are having unique impacts on my body. Yes, some of it is on uh on on weight control and, you know, all the things I've learned from your books, uh but also, you know, on angiogenesis, on DNA, on our gut microbiota, you're you're really you I want people to really think about the wider aspects of what we're consuming on a day-to-day basis. And whole foods are just fantastic at giving us that that huge selection of of different uh nutrients.
Dr William Li: Diversity is very important, moderation is very important. Um finding unique new combinations of things are really important as well. This is all, by the way, um not news, but this idea was present in, you know, the culinary traditions of India, Southeast Asia, uh Thailand, China, Japan, Indonesia. You know, some of these really amazing cuisines, they chose these very same ingredients that I write about. I in my new book, Eat to Beat Your Diet, I I write about 115 ingredients that all have metabolism activating properties. They come from Asian cooking traditions, found in the recipes, and they're also in the largely in the Mediterranean traditions as well. I call it Mediter-Asian because that's how I actually eat and navigate between these two worlds, Mediterranean and Asia, because I I spent a gap year living in Italy and in Greece. I think the last time I talked I spoke to to you about this. Um uh and by the way, Mediter-Asian, which is the term I give it of how I eat and I encourage other people to eat for a healthy metabolism, isn't a new concept. It's a very old concept that dates back 2,000 years back to the days of the Silk Road, which is the greatest trading route in human history that connected um Asia to the Mediterranean. Back then, 2,000 years ago, you know, um traders riding on camels and working in caravans, when they met each other on this road, they traded ingredients, they traded recipes, they shared food with one another. They stopped at the roadside and they ate other people's foods. They had diversity. And that's what I want to encourage people to to lean into, to realise that, you know, yes, in this era of really sophisticated science and my gosh, there are pharmaceuticals now that can actually help you lose weight, fight body fat. But you know what? Those there are and I think you would agree with me, Rupy, there are certain patients with pathological obesity, life-threatening obesity that probably would really benefit from some of these pharmaceutical approaches and other whole, you know, whole body approaches to treating excessive body fat. But for most people to jump on that bandwagon, I really discourage it. And the reason is, I mean, there's there's many reasons because they're toxic, they're expensive, you know, there's side effects. And by the way, because they're also approved for diabetes, people that are actually um uh diving at the at using the Ozempics and the Wegovys, the semaglutide class of GLP inhibitors drugs, agonist drugs, what they're doing is they're depriving diabetics for the medicines they need to treat their diabetes. There's shortages of these drugs that are now going on around the world. It's it's kind of ridiculous. But I'm on the Doctor's Kitchen podcast, so I got to give you my biggest reason for it. Okay? These drugs, the GLP-1 uh agonist drugs, semaglutide, Wegovy, um Ozempic, of the world, you know what they do? They work by cutting off the appetite in your brain. They make you not hungry. They kill the pleasure, they kill the joy of food. How sad is that for a typical person who doesn't need that? I personally find joy every single day. I look forward to every meal in which I can make a choice of something that's going to light up my taste buds, light up my health and give me joy as well. So for me, I tell people that it's time to get off the bandwagon of these um, you know, weight loss drugs and it's time to rediscover the joy of food. And for people like you and me, Rupy, where we're doctors, we know the science, we also know how to cook. It's really time to lean forward into your food and you can love your health and love your metabolism and love your food all at the exact same time.
Dr Rupy: Yeah, I I 100% agree. I couldn't I couldn't have put it better myself. And, you know, in in the context of pharmaceuticals versus pharmaceuticals, F A R M A, um you know, the the the sort of purpose uh and the reason why I started the Doctor's Kitchen in the first place is to increase that time span by which we we don't need to use drugs. Um and we can we can push that further along. So actually, you know, we can sometimes avoid or at least uh uh minimize the amount of time that we have before we have to use things like drugs if it gets to that point. So I I completely agree with um, you know, especially in the context of overuse, um and and we have the same problem over here in the UK, polypharmacy has been very recognized by the Royal College of General Practitioners, the Royal College of Physicians. So, you know, it's it's definitely something that uh hopefully will allow food to come more so into the discussion, but also, you know, from the perspective of pleasure and enjoyment, you know, it's one of the the fastest routes to to joy. Um and and and hopefully we can inspire more people to do that. You you mentioned the the stems of mushrooms there, and that reminds me of another section in the book where you talked about the stems of broccoli and particularly it having a high concentration of sulforaphane. And so sulforaphane is something that I think, you know, is absolutely uh fascinating. Um I wonder if you could talk a bit more about brassica vegetables and and broccoli if you will, because uh you know, having your greens every day, that's definitely something that's uh high on my agenda.
Dr William Li: Yeah. Well, look, I I want to talk about um the whole class of brassica vegetables. Most people go into the grocery store and they don't the word brassica doesn't come into their mind. But you know, what I write in my book, Eat to Beat Your Diet, in the second section where I talk about foods and there's 115 foods in there, I write it with the reader in mind, imagining the reader to be um riding in the grocery store of my shopping cart, the way that you might have when you were a child riding in your mother's shopping cart and having her push you along through the grocery store. So I actually take people on a journey on a tour of the grocery store, the supermarket, and and whispering in the ear what to pick out to put into the cart. Brassica actually is a big family of of leafy, stocky vegetables um that um all contain sulforaphanes. Now, sulforaphanes, they're called sulforaphanes because that's the natural bioactive that has a slightly sulfurous tinge to it. That's why broccoli tastes the way it tastes. That's why cauliflowers taste that way. That's why bok choy has not only a little crispy bite, it's got a little bit of a of a um of a of a smoky taste to it, right? So wonderful things. Um and so the the key is that walking into the grocery store, it turns out that broccoli has sulforaphanes and most people who eat broccoli eat the treetops. And if you get frozen broccoli, that's okay too because they're often flash frozen. And but the thing is you're only getting the treetops, which does have sulforaphane, but research I and other people have done has shown that the stems of the broccoli, broccoli plant, by the way, is not just a bunch of treetops. All right? It is one giant stock like a telephone pole with the treetop on top of it. And so most people who go to a farmer's market will know that, you know, when you bring home the broccoli from the farmer's market, you cut off the stem. A lot of people used to throw away the stem. For God's sakes, keep the stem, cook with it, sauté it, slice it up into medallions, purée it, make it into a soup, add a little oregano, a little extra olive oil. You know, there's all kinds of delicious things you can actually do with the stock because there's there's twice as much of the sulforaphane. And by the way, there's also baby brassica. Baby brassica is like broccoli sprouts. It turns out, if you look at the sulforaphane of a of a grown-up broccoli, if there is such a thing, adult broccoli, mature broccoli, I should say, the baby broccoli is only three to four days old. It's just picked. It's a it's a tiny little sprout. A little nutty flavoured. Actually, it's quite nice. You can sprinkle it on a salad, you can sprinkle it on, you know, um some fish, whatever you however you cook. But it turns out that um the sulforaphane levels in broccoli sprouts is 100 times higher than the sulforaphane levels in an adult broccoli. So small but mighty are the broccoli sprouts. But it's not just broccoli. Bok choy, uh Swiss chard, uh uh cauliflower, there's a whole gamut of these incredibly delicious plant-based brassica vegetables that you can go into the regular grocery store. This is not difficult stuff. I write about some unusual foods in my book, Eat to Beat Your Diet, that that require a little bit more searching online to find them. But for the most part, you know, the things that you would just normally wheel your cart by and maybe ignore, I'm asking people to take the time, read the book, realise that these things are actually wonderful, they taste wonderful and they're wonderful for your metabolism. Please try them. Oh, and by the way, not everyone could be um handy in the kitchen. And some people will go, bok choy, I don't know how to cook a bok choy, you know, like that's too much for me. I try to say there's really great news. You should be an adventurer. Have your tap into your adventure spirit. If you've never cooked bok choy or Swiss chard or, you know, or endive, anything like that, no worries. Even when you're in the grocery store, you can actually type in the bok choy, for example, in Google, hit recipe and then hit video. And you will up the search will come up videos of people who know how to cook this food, this bok choy, and they will show you with passion, with love, exactly what kind of ingredients you need to knock out a dish that's going to look great. You your mouth will be watering at the end of that short video.
Dr Rupy: Yeah, absolutely. Uh and you might even serve some Doctor's Kitchen cooking videos, you never know. Uh So I I'm going to ask you some impossible questions now about spices. Now, what are your go-to spices? If you're anything like me with my spices just behind me as well, you know, there's just way too many for me to to to dial into exactly which ones I want to have in my pantry all the time or in my in my cooking. So what are your go-to spices? Um particularly through the lens of uh eat to beat your diet and and uh and fat control.
Dr William Li: Yeah. Well, look, let me describe that from the flavour and culinary cooking perspective because I think that's what most people will relate to. I could name every spice and I can tell you what is known about the bioactive in them and I can tell you what the mechanism is, but you know what, people are not going to remember that. But what people will remember is I approach spices using that lens of Mediter-Asian cooking and eating. All right? So what are the spices that are used in both the Mediterranean and and Asia? Chili peppers, white peppers, black peppers, turmeric, lovely ways of actually cooking. Um saffron, a sort of a near east uh spice, lovely flavour, very kind of expensive but really good. Then you start going into um like in the Mediterranean, basil or basil, rosemary, uh uh sage, incredible flavours to it. Some of them are are exquisite um flavours that that are very unique like lavender. You can also use that to actually flavour your food. Um all spice, cloves, cinnamon. Cinnamon, by the way, uh actually is originally from Asia. They imported the the cassia bark uh from from China uh around the world and it became it was traded on the Silk Road as part of Mediter-Asian uh trading of ingredients, um because it's a dried bark. Those are some of my favourite types of spices that I naturally go to. You know, curries, you know, you can either buy a pre-mixed curry powder, you can mix your own curry, have some fun uh uh doing it. These are just kind of the my go-tos that I automatically think about. Paprika, smoked paprika, pimento splet. I mean, these are the things that you would find, you know, if we went to my kitchen and opened up my cabinets, these are the ones that you would actually find um with low filled, quarter filled bottles because I use them so often in my cooking.
Dr Rupy: Yeah. Yeah. I mean, it's kind of the a similar way in which I describe it, you know, people always ask me about the benefits of turmeric or the benefits of cinnamon and and I always say, look, you you can find the the a similar sort of collection of bioactives in your typical culinary herbs that you'd find in a in a UK kitchen, whether it's basil, whether it's thyme or, you know, tarragon or whatever it might be. You don't always need to go for the exotic ones. It's great if that's the way you want to cook and that's the way you like to cook. But really, it's just a case of getting the spices and herbs in your diet because it has all those benefits. And, you know, through the lens of of uh metabolism and weight control, I think you can look at it through that way, or you could look through other lenses as well, like improving your gut and improving the palatability of all the different foods that serve your your um immunity and and gut health as well. So, um I'm glad you started uh with that sort of uh perspective because it mirrors mine as well.
Dr William Li: Yeah. Well, and by the way, you know, the spices all come from plants and the spices, the little pieces of the spices, many of them have dietary fibre, like basil, for example, or thyme or rosemary. So you're actually feeding your gut bacteria as well as getting this incredible flavour. So it takes a little bit of practice. I think with spice, you have to, you know, it's kind of like being an artist. I I I think of cooking with spices as a little bit of the art of cooking. How much how much red paint do you want to use? How much pigment do you want to use? I don't know. It's a little bit different for everyone. And and your own taste buds and and the combinations. But again, I I think the way that I really try to approach it is don't be intimidated by this stuff. These are thousand-year-old traditions that people have figured out what are some of the healthy ingredients to combine together in ways that are pleasing, that give you joy, you know, that and that are not that difficult to do. Sure, you can find complicated recipes, but I'm saying you can find simple recipes. And as you say, a typical kitchen in the UK or the US or frankly any place in the world, you can find some of these spices. They are flavour enhancers. They're the original way that we actually made food taste great long before the industrialization of food to make ultra processed food with these synthetic artificial flavour enhancers. And so we should just go with the old ways because they're really great.
Dr Rupy: Yeah, yeah, absolutely. Um look, as we as we bring this conversation to a close, um I'm sure we can carry on and, you know, if there was a kitchen in front of us and we were in the same place, we would be cooking alongside this as well. So we definitely have to do that. I'm going to hold you to that for sure. Um you know, leaning into your experience in the pharmaceutical industry and drug discovery, you know, you're you're really using that sort of scientific lens to to go into, you know, the epidemiology studies, the mechanism that we typically look in in and at lab studies, but then also human trials as well. How do you approach looking at a particular food in that manner? So for any budding scientists out there or even medics and and, you know, people in the nursing profession, people interested in this, how would you advise people to approach this subject of food as medicine?
Dr William Li: Great question. Um because I want more people to kind of like step into the field and really understand how wonderful it is. I think there's kind of two components to it. And I don't want to get away from the first component, which is what we were just talking about, which is food is wonderful, it tastes great, it brings joy, it's part of tradition, um and people, honestly, it's part of our humanity. It connects us to the land around us and and and our and our cultures and our history. So please don't forget the tasty part of food. That said, if you're trying to get into the research field, let me explain to you how somebody studies food as medicine. This pear, which I showed earlier, could be might as well be a a pill, a capsule in a in a drug. And how do you study that? Well, you look at what's been studied in the lab. If you look at, if you go into PubMed, which is one of the search engines for medical literature, and you type pear and you type preclinical and you type bioactive as an example, all the search results will come up will show you what people have actually been doing in the lab to understand what how a pear might actually work. When you feed a lab animal a pear, what happens? When you extract from the pear and put it into cells, what actually happens? That's a really easy way to kind of like scratch your itch of curiosity to learn something about that. You want to step it up, take out the word preclinical, hit the search engine again and put pear bioactive clinical trial. Now you'll actually see what clinical trials have been done in in people studying pears. There may not be a lot, but you'll see what has been done and that will actually, you know, really be fascinating for you to realise that some people actually study pears. By the way, there was a metabolism study in which they gave people two pears to eat before lunch every day and it actually shrank your waistline by using the chlorogenic acid to burn body fat over four weeks, just two pears. Oh, what kind of pears? Bartlett pears and Anjou pears. Read the paper. So again, you know, these are the fascinating things that for anybody to kind of dive in if they're interested. And then, you know, if you really want to find out, well, okay, clinical trial is interesting, but, you know, nobody is really doing the randomized double blind placebo controlled, you know, multi-center um uh trials on only pears because that's what people do with pharmaceuticals and it takes millions or billions of dollars to do that. You don't need to know, you don't need that to actually demonstrate the goodness of a pear. But there is a clinical trial, you want to remove clinical trial from that, put epidemiological study. And now you'll find what research has been done looking at pears across big populations to see the correlations with health or disease, either lowering the risk of disease or elevating, improving the levels of health. That's a simple way that anybody with access to a computer, the internet can begin to dive in and take any ingredient and start to look at it. And so for anybody who wants to get involved in this field, if you're a young researcher or a medic, you're interested in exploring it further, you know, um you can also just kind of look at conferences on food as medicine. There are literally conferences being put together on multiple, probably over a dozen uh conferences um that that are actually beginning to study this new this budding field of food as medicine. Register for the conference, attend it, learn what's there. The conference that you and I were at Rupy was fascinating because um uh last year because we were watching researchers from all around the world present their data showing the power of food in the human body. And so this is like a super easy way to do it. But I never want people to forget that food is part of our humanity. So as intellectually fascinating and as mechanistically compelling as a food might be, as cool as it might be, you know, the reality is that food should taste great. And if you're you're not going to be eating it um uh if if it tastes crappy, and you're going to and you're going to want to learn, you'll be avidly looking and seeking out for more knowledge and more opportunities and more ways to activate your taste buds, the more you learn.
Dr Rupy: Absolutely. Well, William, I can't wait to do this again in uh in person in front of a a hob, a couple of saucepans, uh and uh a good selection of delicious food that we can knock up together. So, um yeah, until then, uh thank you very much. The book's fantastic and uh I can't wait to help push it up for you over here in the UK and beyond.
Dr William Li: Thanks very much. Looking forward to getting together and cooking.
Dr Rupy: Absolutely. Absolutely.
