Feel Better, Live More with Dr Rangan Chatterjee - BITESIZE | How To Eat To Boost Your Body’s Natural Defences & Avoid The Foods That Weaken Them | Dr William Li #647

Episode Date: April 9, 2026

Today’s guest passionately believes that the decisions we make every day about what we eat have a huge influence on our overall health. Feel Better Live More Bitesize is my weekly podcast for your mind, body, and heart. Each week I’ll be featuring inspirational stories and practical tips from some of my former guests. Today’s clip is from episode 450 of the podcast with internationally renowned physician, and bestselling author, Dr William Li. In this clip, he explains how the foods we eat could either support or weaken our body’s natural defence systems, and shares some simple, practical ways to make better choices every day. Thanks to our sponsor ⁠⁠⁠https://thewayapp.com/livemore  Show notes and the full podcast are available at https://drchatterjee.com/450 Support the podcast and enjoy Ad-Free episodes. Try FREE for 7 days on Apple Podcasts ⁠⁠https://apple.co/feelbetterlivemore⁠⁠ For other podcast platforms go to ⁠⁠https://fblm.supercast.com. DISCLAIMER: The content in the podcast and on this webpage is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or other qualified health care provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website

Today's bite-size episode is sponsored by The Way. I have tried so many meditation apps over the years, but I've never come across one as good or as effective as The Way. I find it a fantastic way to start off each day, and it has really helped me feel calmer, relaxed and more present. In fact, I love this app so much that I recently decided to invest in the company and join them in their mission to get more people meditating. meditation has been shown to have all kinds of benefits, reducing stress, increasing calm,

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your weekly dose of positivity and optimism to get you ready for the weekend. Today's clip is from Episode 450 of the podcast with internationally renowned physician and best-selling author, Dr. William Lee. In this clip, he explains how the foods we eat could either support or weaken our body's natural defense systems and share some simple, practical ways to make better choices every day. I think one of the greatest things about food and health is that it actually puts the agency of choice into our own individual hands. And so we make our own choices. One of the interesting things that is very clear is our body's health defenses, the five of them we talked about last time, our circulation, our stem cells, our healthy gut microbiome, the ability for our DNA to protect ourselves, our bodies from the environment. And also our immune system, these systems for us to reach our health potential, we want to make sure that they are not squashed inadvertently by foods that we have gotten used to eating.

And so let's talk a little about some of those foods that actually impair our health defenses. That's probably the best way of thinking about what to avoid. Now, we know that added sugar is something that is very, that taxes the body's metabolism, right? So if you have a little bit of sugar in fruit, you know, from natural sugars, that's fine, because you're getting a lot of other stuff in fruit as well that, in fact, helps your metabolism and helps your body's ability to be able to digest and metabolize fructose and glucose and use that fuel into your body. But if you drink soda, you know, to have those 10 teaspoons of refined sugar that are dissolved

invisibly in whatever colored fluid we might be drinking, it tastes great, quenches your thirst. It kind of our mental blueprint is that, you know, this is something you use to sleek your thirst in a hot summer day. And I can tell you that the hyperglycemic state, your body can't handle 10 teaspoons of sugar at the same time. And think about the people that chug an entire can of soda, right? I mean, I've done it myself. There's no way that's good for us.

So that overwhelms a lot of our systems. It overwhelms our stem cells. Our stem cells cannot adequately function, properly function, to help us regenerate when there's too much sugar around. You know, sugar is a concentrated material. It's a solute, meaning that it's dissolved in water. And when there's a lot of things, Think about when you're in a swimming pool or if you're swimming in the ocean for a long period time.

What happens is the water gets pulled out of your skin or even in a bathtub. Your skin gets wrinkly because you've sucked out all the water. And that's basically what happens to these cells in a high sugar environment in your blood. So I would say added sugar with sodas that are so popular. That is something that sits on your health defense systems. Too much sugar also literally damages the ecosystem of your gut microbiome, unhappy gut, unhappy immunity. You know, we all want to actually be as strong immunologically as possible.

And then, by the way, let's kind of just take one step over to the kissing cousin of regular soda, which is diet soda, right? So here's the thing. I just told you, you know, we might want to cut down or cut out regular soda. So what do people say? They say, well, don't worry, Dr. Lee, we just go over to the diet soda. No worries. I drink the diet version.

It's much better for my metabolism. Well, science tells us it's not true. And the irony is that people who drink a lot of diet soda, with the purpose of not getting a lot of carbs from refined sugar, actually still gain weight. This is a kind of a paradox that now makes sense because scientists have figured out that many of the artificial sweeteners used in diet sodas actually harm our gut microbiome. And so when you're drinking that soda and that artificial sweetener, you know, you get that sugar hit on your tongue to go to your brain. Man, it's pretty sweet. But all those chemicals

go down your gut and they're feeding our gut bacteria. And the gut bacteria really don't like these synthetic compounds, these artificial sweeteners. And so they revolt. And as they're revolting, they're actually literally drowning in these artificial sweeteners. And that is bad enough because our gut bacteria actually, you know, helps to lower inflammation. But our gut bacteria also controls metabolism, our insulin sensitivity. So when that gets upset, guess what? Our actual blood sugars raise and we actually have poorer metabolism of our energy and we actually start to gain weight anyway. So that's, you know, kind of just two examples, but there's a lot of other foods that we might want to be careful about. Yeah. So in terms of categories and types of foods that

we should think about limiting or avoiding, the first thing you went to was those drinks with added sugar soft drinks, fizzy drinks, soda. I hope it's generally well known that actually those things are damaging for our health, our teeth, and you beautifully explained why that is. Now, before we go to diet drinks, because I'm really glad you brought that up. Full sugar, fizzy drinks. Is it just the sugar that's causing problems because it overwhelms our system and we can't process it? Or is it something else? Is it the sugar and the chemicals and the impact they have on other aspects of our body's health? And potentially, those five defense systems, what's going on there? Is it just the sugar or is it something else? Yeah, the soft drinks, the sodas that we see so commonly

around us, it's part of everyday modern life. Once actually the big industries came in and turned it into a marketing buzz, here's where it morphed, went from food juices that actually had some carbonation, which is just gas, CO2, and that's okay. But they figured out how to put chemical flavorings that actually mimic fruit flavoring. And then, of course, nobody really wants to have just a plain, watery-looking carbonated drink. So then they started to add artificial coloring. And then they started to add preservatives. And this goes to the importance of reading a label. You know, I'm an explorer, so I love to actually try new things. If I saw a drink in a store that seemed appealing. The first thing I do is I take a look at the label. And so if you are creeped out

by not being able to pronounce, understand, identify the ingredients on a beverage, you should follow your instincts. That's probably not something you want to put in your body because your body's not hardwired to handle those chemicals. Yeah, I think that's great advice, something I use with my patients as well. People say there's always exceptions. Yeah, there are exceptions. But as a general principle when looking at ingredient labels, I completely echo that. If you don't recognize it, you know, maybe give it a miss and choose something else instead. You mentioned sugar and these soda drinks that we know it certainly even small amounts consumed regularly can be quite damaging for our health. And then you went to artificial sweeteners in these diet drinks. Now I share the same perspective

as you do on this, but it does appear to be a very divisive topic. with the public, but even within science and within medicine, this whole topic of whether artificial sweeteners are good, bad or neutral, seems to get a lot of people's backs up. I certainly take the precautionary principle with my patients to say, listen, that I've seen enough data that suggests it's having a negative impact on the gut microbiome, so I would prefer to take that precautionary approach and say, let's try something else. What is your view on that, and why do you think it's such a divisive topic? Well, first of all, every kid loves candy, right?

Me as well. And I think that, you know, sugars, the candies, they're delightful. And there's nothing wrong with being delighted. The brain's also hardwired to actually go after sweet things, right? I mean, it's part of our instinct as animals to, you know, just like the lion on the savannah goes after the antelope. I think humans, you know, on the street go after candy. It's one of those things that just we're hardwired to go after sugar. I think there are industrial interests that actually, you know, pose counter arguments to the harm

of sugars and artificial sweeteners. And by the way, I do want to actually bring this up because I think it's important. Let's not character assassinate categories. I think that's really important. So artificial sweeteners, let's be specific. What I was referring to are things that are not refined sugars, the powdery white stuff that you would buy in a supermarket. The artificial sweeteners are the ones that are chemically synthesized, not natural, that actually

have been designed to activate the sugar receptors on your tongue and mimic sweetness. Right. Okay. And there's many different kinds. Some people could consider artificial sweeteners stevia. Now, stevia is a natural sweetener, but it's still artificial when you compare it to refined sugar. And what about, you know, like some people use monk fruit, which is also a natural sweetener, which is the same thing as refined sugar.

It also activates your sugar taste buds. It's more natural. And then what about our spartame and circolose? And what about all those other kind of chemical names that you can't pronounce? And so I think as we're talking about this now, we need to say categorically, you know, I think excess natural sugars in product form added to food. It's added sugars tend to be unhealthy if you overconsume that. And so does it is just one of many examples. with lots of added sugar.

Artificial sweeteners is not one category. It's a lot of different types of things that are used in place of refined sugar. And what I would say to be a savvy consumer, you know, just know that there are more natural versions of those. I think stevia is fine. However, there are stevia that actually are not really all stevia. You pick up the package, you look at the ingredients

and you find even though it says, stevia, you look at the ingredients and you actually see that there are other things that are added to it. We cannot forget when you buy ultra-processed food in a package, stuff has been added to it almost certainly, even to preserve it on the shelf that may or may not be good for you. And one of the big advantages we have right now, every one of us carries around one of these, a mobile phone.

And so if you don't recognize something and you're curious, go ahead and type it in and search that chemical to learn something about it. That could actually make the difference between whether you put it in your cart or not. Yeah, I love that. a very empowering way of looking at this, to put the information in the consumer's hands and say, right, you start as much as possible to make these better decisions because you know that this one's going to lead to health. This one's probably going to not promote my health over a period of time. Also, you know, in our first conversations together, which if people haven't heard,

I'd highly recommend they go back and listen to. One of the things I really liked about your approach was you said, well, let's put into our body foods that support these five defense systems. can do that and support them, we raise the bar, we become more resilient. Therefore, we've got more headroom to actually deal with the insults that are going to come in in life, whether that's DNA insults from pollution, or whether it's the odd thing that we creep into our diet that we probably know isn't the best thing for us, but, you know, we just fancy it now and again. And I really like that approach. And I know we're starting off this conversation, focusing on some of the things to avoid. We're very quickly going to get onto the things that people can put in. But yeah, I really,

really appreciate that. The most important thing that we as doctors can do is to listen to our patients and hear them out and try to understand where they're coming from and what's important to them. I always ask my patients, you know, what do you eat? What do you like to eat? What brings you joy when it comes to food? That question usually can elicit an answer. I'm very careful not to ask that question judgmentally. What kind of negative foods? How much for steak do you eat? I never ask that. I always sort of say, like, tell me about what do you enjoy eating? What brings you joy? What are some of the favorite things that you like to eat? And, you know, again, it's that conversation that invites someone to look deeply within them. And I think that so often we get distracted,

we don't have that opportunity to ask ourselves, something simple like, so if we had a choice, what would we want to eat? What brings us joy? And my strong belief, is if we want people to get on a better diet, to get them started, and to keep them going on it, we want them to actually feel like it's not a heavy lift, it's something that's doable. And I think there's nothing easier than to say, hey, you know what, something that already brings you pleasure and joy, something you enjoy to eat already is healthy. So let's start with those things, because you already know you love them. So in my book, it could be disease, I have lists of like 200-some foods.

I always tell people, you have my book, get a Sharpie. Okay. I say a Sharpie, like the marker, permanent marker? Yeah. Because it's permanent. You have to make a commitment, all right? And circle the foods that you enlist that you already like. No, actually, that you love.

All right? I don't care if it's just one or two. Almost everyone I've met has been able to circle like 10 of them or more. But if you find a food that you already love, that's healthy and good for you, that activates your health defenses, you are already one. way ahead of the king. Love that. Very empowering approach to people. Apart from these drinks that we've covered so far, any other sorts of foods that we should generally try and avoid, let's say when we're in the grocery store or the supermarket, anything we should think about? Yeah, so I think,

you know, largely for the same reasons of having chemicals being put in our body that we don't really want, ultra-processed foods, foods that come in a box, foods that got lots of ingredients and lots of preservative and chemicals inside them, things that they say that your grandmother, if you showed her, might not recognize as food or a great-grandmother, perhaps. Ultra-processed foods as a group tend to be associated when we look at populations with poorer health outcomes from diabetes, obesity, cardiovascular disease, and even cancer. And so, again, you know, even though I said we should be careful not to overgeneralize, it is true, things in a box, things in a cans, things, you know, that are manufactured.

at scale and intended to sit on the shelf for months or maybe even years, tend to draw the attention, my attention anyway, that really is worth reading a label and knowing what it is you're putting in your body. So ultra-processed foods, I think, you know, processed meats are another food product that actually are classed as a carcinogen by the World Health Organization. Now, what kind of process meats are we talking about? We're not talking about that. The air-cured salami from Sardinia, you know, that have been.

made in the same way for thousands of years that people eat sparing amounts of, you know, as part of a more well-balanced Mediterranean traditional meal. I'm talking about the deli foods. You go in there and they're slicing stuff, you know, from a big lump that looks nothing like the animal from which it came. And some of these cured sausages, if you visit a sausage factory, I had a patient once who actually worked as an inspector in a commercial sausage plant. And he told me that he used to have to change his.

boots every month, rubber boots walking in there because the stuff that splashed out of the pool in which the sausages were essentially embalming in for preservatives and for flavorings would actually dissolve the soul of his rubber boots. That made such an impression on me. I'm still talking about it 20 years later. Yeah. And we're sort of removed from that process, aren't we? We don't see that? We don't see that on videos. We just see the nice packaging and the clever marketing. copy on there. And so I think that's really, really important. And I really like the way you made that distinction there. One thing I must ask is, in our first chat, you mentioned many foods which have super helpful properties. Two that come to mind are Kiwi fruit. You mentioned how they can actually

help repair DNA, which is remarkable. The amount of people who stopped me in the streets since then to say, Doc Chachi, since that conversation, I'll be buying Kiwi. I've been buying Kiwi. I've heard it over and over again. So that's credit to you, Dr. Lee. But also, tomatoes. you mentioned, but many people contacted me, including some family members to say, listen, I don't tolerate Kiwis. Like I get a really bad reaction when I have them. I don't tolerate tomatoes. I get a really bad reaction when I have them. And of course, this is individual, because not everyone has intolerances or reactions to certain foods. But for people who've heard your great advice and wanted to bring those in, but thought, well, I can't have that. How would

you respond to them, like, what would you say to them to give them some sort of hope? Yeah. Well, look, what I always tell people is when it comes to food and health, it's not just about the food or any single food, whether it's a Kiwi or tomato. It's really about how our body responsibly put inside it. So if you don't like Kiwis, can't find Kiwis or are allergic to Kiwis, all right? Those are three easy reasons or can't afford a Kiwi. You can do a swap out. Okay. So what are in Kiwis? Kiwi's got vitamin C. It's got fiber. What are some other foods that actually have vitamin C that also have fiber? Red bell pepper can actually have that. What if you're like, well, I'd like something a little sweet. Okay, guava that also has vitamin C and it's also got fiber as well. Now, the research that we discussed last time about the Kiwi was research done with Kiwi itself. But the properties of the kiwi, which is vitamin C and fiber, and some of the other phytonutrients, those can be found in other fruits as well. So Kiwi, I always say, like, if you want to kind of stick with the research, you got to go with the food that was actually

studied. But the properties and principles allow you to actually think about how to swap things out. What a tomato? Great example. Guess what? Lycopene, if you want to get the lycopene benefits, you know, lowers risk of breast cancer by 20%, lowers risk of prostate cancer by almost 30%, protects your DNA against sunlight. What else is lycopene? Watermelon. watermelon has lycopene as well. So maybe you don't like tomatoes. Maybe you can't get tomatoes. Well, what about a slice of watermelon?

And so again, think about why something is beneficial for you. And then if you can get that food, that's perfectly fine. If you need to swap it out because you can't find that food or can't afford that food, think about what else might be a good standard. Yeah. And at the end of the day, it still has to taste good for you. So maybe you don't like tomatoes, but you like watermelon. Maybe you don't like kiwi, but you actually like guava.

Yeah, I love that. And in my experience, also when we go to more of these whole foods that we can tolerate over time, actually, I find that we often repair our gut and then we become more tolerant of foods that we previously couldn't manage. I'm not talking about over allergies, but a lot of food intolerances, I've definitely seen that that happens. And I think moving to a whole food diet, no matter who you are, no matter what your current state of health, there's very little side effects or negative side effects. I should say. There's many effects, mostly beneficial effects, very few negative side effects of doing that. Any closing words to my audience who might be confused, inspired, empowered by what you said?

Any closing thoughts for them? You know, I have one motto that I want everybody to just sort of try to take to heart, which is that when it comes to food and health, I really believe that you should love your food to love your health. both can happen at the same time. You know, we should find the foods that we love that are good for us and really lean into it. And that's the best way to have a long and enjoyable life. Hope you enjoyed that bite-sized clip.

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