Gut Health Expert on How Fiber Optimizes Your Microbiome | Dr. Will Bulsiewicz on Health Theory

The single most powerful predictor of a healthy microbiome, of a bio-diverse microbiome, was the diversity of plants in your diet. Hey everybody, welcome to another episode of Health Theory. I am here with somebody that is going to challenge so much of what I've been thinking, and I'm excited for you guys to hear this stuff. It's really powerful. Dr. Will Bulsiewicz, thank you for joining me today. Tom, it's a it's a pleasure to be on the show with you, my man. And I have to tell you that for the listeners who are at home right now, you said my last name without asking me how to say it, and you said it perfectly. And so I have to give you props right off the bat because in my entire life, and I'm 40 years old, I don't think I've ever heard someone say it with such confidence. That's funny. And so I have to give it to you there. Well, thank you, good sir. It's uh I had to rehearse that like a zillion times. I have said your name now so many times. I didn't want to didn't want to mess it up, so glad I nailed it. And now I want to dive into So, about six or seven years ago now, um my wife had just a catastrophic event, and people that uh are familiar with the show will have heard this story, so I'll keep it quick, but uh went from thinking everything was fine, and she has a threshold event, and then now all of a sudden for a year our lives were completely put on hold from a microbiome issue. But at the time, I had probably before that happened, only maybe six months before that, learned that there was a thing called the microbiome. And the punchline, of course, is that I had to start researching about the microbiome, and that was why I ended up doing this show cuz I was reading so much about the microbiome. Uh but where we ended up was like vegetables are are coming for you. They are You have to be so careful with vegetables, but meat meat you can eat with impunity. And that was like our first sort of safe place. And it's only been in the last couple of years that I've started to go, "Ah, god, like all or nothing stuff just makes me nervous. So, let me really try to push the boundaries and see what the vegan vegetarian community have to offer." So, I'll say that I've gone from um really comfortable with a true um all meat carnivore diet and less interested in vegetables to now probably about 60% of my calories come from animal products and 40% from vegetable. And I'm perfectly happy to take it all the way to 100, but there's going to be a few things today that I need to better understand. So, with that, let us begin with one simple question. How do you rebuild a microbiome? And to answer that, if you can just tell us first like what is a microbiome for people that aren't super familiar. Oh my gosh, Tom. I have so much that that you have loaded you have loaded me up here with stuff that I want to talk about. So, you know, we think of ourselves and we were raised you and I are probably pretty similar in age. We were raised thinking of ourselves as these powerful autonomous creatures. We're the humans. We're the masters of our domain. And what we have failed to realize and understand until very recently is that we're not alone. Covering us from the top of our head to the tip of our toes are an innumerable number of invisible microbes. And these microbes when I say microbes, what I'm talking about, I'm talking about bacteria. Talking about yeasts. I'm talking about these things called archaea that have been on this planet for 4 billion years. Talking about potentially parasites. Um and there's a role for viruses, too, by the way. So, now they cover all external structures and the number is kind of absurd. So, you know, for example, if you hold up your thumb and you take a look at it, right there on your thumb, there are as many microbes as there are people in the UK. It's crazy to imagine um because they're invisible, but they're there and they're most concentrated inside of our colon, which is our large intestine. We have 39 trillion microbes. That's the equivalent of taking 100 galaxies full of stars, compacting it down, and putting it inside your intestine, and there they are, 39 trillion microbes outnumbering your human cells. You have more microbes living in and on you than you have human cells. So, now this microbiome, Tom, they're not just there. They're not just freeloaders like leeching off of us. They are there with a purpose. They have been there since literally day one of humanity. So, if we want to talk about evolution, forget human evolution. We need to start talking about coevolution. Coevolution, which is humans and their microbes rising and falling together. And that's what we've done over 3 million years. And actually the DNA, Tom, if you think about it, we cracked the genetic code 20 years ago. And when we did this, Bill Clinton was the president, and he actually called a press conference, and like Tony Blair was there, and all these famous people were there because they thought that they were going to cure cancer and reverse heart disease by cracking the human genetic code. It hasn't worked out. We still have cancer, and we still have heart disease. Why? Because 99.5% of our genetic code is not ours. 99.5% of our genetic code comes from these microbes that live inside of us. Not to mention that our genetic code that we have, these microbes have the ability to flip switches and actually affect which genes get turned on or get turned off. We call this epigenetics. People have heard of this epigenetics, your microbiome plays a critical role in epigenetics. And Tom, you know, this evolutionary pattern that took place, it's more than just them regulating our genetics. They're affecting our digestion, our access to nutrients, our immune system. 70% of our immune system lives inside of our gut. That's like the most concentrated source of the immune system. They're affecting our metabolism. They're affecting our hormone balance, our brain health, our mood, our cognition, the way we think. It's like you take a step back and you just realize everything that matters in human health, these microbes are playing a part in it because it's talking about ecosystems. And ecosystems can be massive, right? Like our planet, we can think of as one giant ecosystem. They could be very large things that we all sort of recognize as the classic ecosystem, like the Amazon rainforest or the Great Barrier Reef. But then like literally living inside of every single one of us, this gut microbiome, this this is an ecosystem. And the same rules that apply to the Amazon rainforest or to the Great Barrier Reef apply to this ecosystem that lives inside of us, where it's about balance. It's about harmony. It's about biodiversity. And when you have biodiversity, what that means is yeah, there's good guys and yeah, there's bad guys, but guess what? They all live together in one balanced harmony and they're all bringing something that they contribute to the ecosystem. And when you start knocking them off and eliminating them, you contract that biodiversity and what you find, regardless of what ecosystem you're talking about, whether it's your gut, whether it's the Amazon rainforest, or whether it is planet Earth, when you lose biodiversity, you you are creating instability within the ecosystem. And that unfortunately is what we're facing in the 21st century when it comes to the gut microbiome for a lot of people right now. Yeah. So, you know, just in going back to my initial thing that I want to make sure that we don't wrap this episode until people know how to rebuild because so many people right now they've just battered it through the things you're talking about now, antibiotics, over sterilization, um terrible diets. So, what what are the things that we start doing that will meaningfully allow us to get that biodiversity and biodiversity is probably where we should start. Assuming someone has hurt their biodiversity, how do we begin to build it back? Well, I think to answer this question properly for you, I have to separate out what I want to say if I were taking care of your wife Lisa 6 years ago versus what I want to say to your audience right now who isn't necessarily in such a dire situation as she was 6 years ago. So, um you know, with regard to the average person who's listening to this show, think about how much life has changed in the last 100 years. Like literally 100 years ago people were still had like, you know, horses and carriages and buggies and, you know, they were going to their local market. Everything was locally sourced. There were no processed foods. And, you know, we didn't have all these chemicals that we apply to our skin or to our hair on a daily basis. And we didn't, you know, we spent a lot more time outdoors. We weren't watching television, watching Netflix 100 years ago. And so, we what we need to do is we need to get back to a more authentic style of life and that doesn't mean rolling around in the dirt. I I I kind of find that idea to be like a little bit silly. It's more that we need to get back to we need to exercise. We need to actually sleep. We need to get away from blue light late in the evening. We need to get away from the foods that are just like completely filled with these chemicals that literally these microbes were not exposed to 100 years ago and now this is making up the majority of calories for most Americans. Talking about the processed foods. So you you think about what are the things in our modern lifestyle that are having a negative consequence and then you flip your attention to how do we rebuild it? And I do want to talk about that in a lot more detail than what I'm about to say. But I think one of the major issues and what I wrote my book about is that we live in a society that is completely devoid of fiber consumption. And fiber is the preferred food of these gut microbes. This is what they thrive off of. They grow stronger because of it. And if we're looking at biodiversity in the largest study to date to allow us to correlate dietary choices and lifestyle choices to the biodiversity within our gut microbiome they found they answered this question. The single most powerful predictor of a healthy microbiome, of a biodiverse microbiome was the diversity of plants in your diet. And that's because every single plant has its own unique way fiber's not just fiber. Like we've been talking about fiber since I was a kid as if it's like it's just Metamucil. You stir the orange drink so grandma can poop. And it's that's not the way it works. Every plant has its own unique types of fiber. Those unique types of fiber feed unique families of microbes. These microbes are picky eaters. Not every microbe wants kale. And so when we make different dietary choices in terms of the broad broadening out the biodiversity within our diet this leads to more different species of microbes being fed and it leads to more biodiversity within our gut microbiome. And we have a couple of studies to back that up at this point, Tom. But you know, transitioning for a moment over to your wife Lisa and six years ago let me just say that if I am taking care of a person, like I personally I think you know this about me. I don't know if your audience knows this about me until right now. I personally am vegan. But I didn't I'm not teaching the science because I'm vegan. I'm vegan because the science led me to where I am today. And I teach plant-based. Plant-based meaning fruits, vegetables, whole grains, seeds, nuts, and legumes. And you said Tom that you're 40% plant-based. And that's about 35% more plant-based than I was 10 years ago. So, to me, I want to take each individual person and I want to move them in the right direction. If I were taking care of your wife Lisa 6 years ago, I wouldn't say to her, "Hey, you need to go vegan." That wouldn't be the conversation. What I would do is I would first try to get her to gain some weight because she's in a calorie deficit and that's why she's losing weight. And I would Look, there are going to be some people that don't like that I'm going to say this, but in that setting, I totally get consuming animal products. Because it is it is high-calorie. And in that setting, in a person who's in a calorie deficit, they need that. And we need to get them back to balance because she is in a catabolic state. But when we get her back to balance, my goal is to start to reintroduce these foods. By foods, I'm meaning the plants. My goal is to start to introduce these gently, low and slow, to rehabilitate her gut, to build it up, and make it stronger. Because what I want get super hard on that in a second. Before we move off the meat thing, I want to figure out why is it if in and we may not have the literature, so maybe this is just a sort of gut instinct, but why is it that for a lot of people and I don't know if it's a majority of people, but there's certainly a contingent of people for whom it's the whether it's FODMAP foods or it's fermented food whatever, there's like vegetables can trigger something, but I don't often hear of somebody that's having that's had a significant disruption to their microbiome, I don't hear often times that they're struggling with um meat. So, what I'm trying to figure out is why is the safe thing to to remove vegetables? Why are vegetables problematic when you have dysfunction? Sure. If the reason why is because we there are an innumerable number of types of fiber that exist in nature. And there's extreme complexity to this fiber. And so as a result, we actually evolved to allow our gut microbes to handle the digestion of fiber for us. So, they have specific digestive enzymes that they use. And you know, Tom, we we actually as humans, we don't have the innate enzymes to digest fiber. If if we were sterile, if we didn't have a gut microbiome, fiber would literally go in the mouth and it would come out the other end. But, we're not sterile. We have a gut microbiome and they have these enzymes that they use to basically break down the fiber into its components and and then release it into basically short-chain fatty acids, which we can talk about in more detail what those are, but we rely on our gut microbiome to break down fiber and people who suffer with food intolerances, it is because they are struggling to break down the complex carbohydrates in their diet. And it's because they lack the enzymes that they need in that moment to process the fiber. Now, if they reduced their fiber intake, they would be able to tolerate it. And in that process, they would actually start to build up the gut microbiome in a way where over time, like a muscle, that muscle grows stronger as you train it. So, when you start introducing fiber, if you go low and slow, you start to ramp it up slowly over the course of time, that's how you go from having a weak muscle to over the course of time eventually building up the strength of that muscle so that it is more capable of processing the fiber. And the end result, the reward for doing that, is that the dietary restrictions go away. And your gut becomes stronger, and you restore function to the gut. And so, there's a great reason for us to want to do this because when we restrict our diet, we feel better in the short term, but we pay the price in the long term because our gut actually grows weaker as a result of those choices. And I would make a quick analogy, I hope you don't mind, to a person who hurts their knee. Right? So, if you hurt your knee, we all know what we're going to do. We're going to rehab. You work your way through rehab, and you know that there's going to be some pain during the process of rehab, but you slowly push yourself a little bit more every single time you go until you build that knee back up, and then you're back to playing basketball again. We have another choice. The other choice is to stop walking. And if you stop walking, you will never feel pain in that knee for the rest of your life. But the problem is your muscles grow weaker, you start gaining weight, you get diabetes, you get high blood pressure, you get heart disease. We know where that's going, right? So, we all make the choice to go through rehab to rebuild the knee, and that's why I'm saying when it comes to the gut, rather than contracting our diet, which makes us feel better short term, but hurts us in the long run. We need to instead have a strategy not to hurt ourselves, but to slowly reintroduce these foods to build it back up so that we can restore function and get back to eating without any restriction. So, do we do we need the like so we need the microbiome to digest fiber? Do we need the microbiome to digest fats and protein? Or is that why that is easier to handle when we have uh dysbiosis? We don't need the microbiome to to process fats and protein. Our pancreas has most of the enzymes that we need to be able to do that. So, the pancreas is cranking out enzymes like lipases and proteases. Lipases for fats, proteases for proteins. Um our our gallbladder and our liver is producing bile, which helps us to absorb the fat. But But make no mistake that all dietary choices, no matter what they are, every single food that you put into your mouth will change your microbiome. And there's a number of different ways that that takes place. Sometimes it's the choice that you make that is enriching certain species because that's their preferred food. Sometimes it's the fact that the other species are not being fed, and so they grow weaker. And so, with every single dietary choice, we are contributing to the balance that exists within our microbiome. Okay, so now So, that's really helpful, and I can't believe that I didn't know that. So, thank you for that information on the meat. Um that makes sense. So, okay, you've got dysbiosis. You've uh antibiotics, washing your hands too much, uh maybe had an eating disorder at one point. You've you know, even I will say that unintentionally I had an eating disorder because I was trying to get really lean. So, I was just basically eating chicken breast and broccoli for like 2 years. It was amazing. I got shredded. I hated my life, and I was inflamed everywhere you can possibly imagine. It sucked, but I got shredded. It was wonderful. Uh so, that was unintentional, right? It wasn't like I was ever out of control or, you know, binge and purge or anything, but I would say that sort of overly restricted would have a very negative impact on my digestion. Okay, so you've made poor choices, didn't do it on purpose. I'm not judging you. Hopefully, you're not judging yourself. All the grace in the world, but here we are. We have a microbiome that's got issues. So, I fully understand the hey, you've got some people the I'm in analogy here, but you've got some of your bacteria, um all the things that are supposed to be there, they're in a weakened state because you haven't been feeding them the things that they need, right? Your vegetable intake is way too limited or non-existent. So, the ones that are still there, I get it. You can make them more robust by feeding them the things you need to feed them. But, I have a base assumption, and maybe this is incorrect, that some of them have have been eradicated. And so, they're not there anymore. And so, now my question is, can I just eat an apple, which has its own microbiome? Can I just eat kale without washing it? Like, how do I get true How do I reintroduce diversity? Yeah. So, this is These are These are great questions, and to be honest with you, some of the answers we're still trying to figure out. So, in terms of like adding microbes back, there was actually a recent paper that came out where they called into question whether or not we should have a daily recommended microbial intake because our food is hyper-sterilized. You know, you think about preservatives that exist in our processed foods. The way that they preserve our food is by retarding the microbes, by keeping the microbes out cuz it's the microbes that break down and process it. So, um so, what are the foods that can introduce microbes back? Well, uh obviously fermented foods. But, living foods, like raw foods, contain a microbiome. All plants, all life on this planet has a microbiome. They looked at an apple. And the apple has 100 million microbes, and over a thousand species that exist as a part of the apple. Is it only on the skin, or is some of it inside the the meat of the apple? Actually, the most concentrated place was the core. Which is the part that we throw out. Yeah. So, I mean, you would think it's on the skin, but actually the most concentrated place was on the core. So, so the point being that when we eat these natural foods, that if you think about 100 years ago, this is what people were eating. When we eat these foods, we are having a microbial exchange that takes place between the food, which is our environment, and the microbiome inside of us, and that may be of benefit to us as humans. All right. So, if we were going to have a daily recommended microbial intake, what would that look like? Or is it your kombucha? Is it a probiotic tablet? Um, how do we intelligently go about taking in our daily microbial intake? You know, I actually, to be completely honest with you, Tom, I would actually pivot in a different direction. Because we're talking about microbial daily microbial intake, which makes us focus and think that we need probiotics to fix our gut issues, and that's simply not true. We have probiotic bacteria, the same bacteria that you will find in a capsule, already living inside of us. And we just simply need to feed them. And if we feed them, they will multiply. And you will have a lot more of them than you would ever find in a probiotic capsule. And they're actually inherently yours, which means that they'll stick around. One of the problems with probiotics is they don't stick. They just run through us. So, from my perspective, do I think that we benefit from consuming raw foods, from consuming fermented foods? On some level, I do. Is that the backbone? Is that the direction that we need to go with things? No. The problem that we have really, Tom, is that the average American is eating 17 g of fiber per day. Our ancestors ate 100 g or more of fiber per day. And the recommended amount is 25 g for women, 38 for men. 95% of Americans are not hitting the mark. And because of our fiber deficiency, our fiber deficiency is causing us to suffer consequences because our gut microbes are not being fed. That's the issue. Okay, so um my hypothesis, just to like put these together. So, my very ignorant, very layman's, like N of 1 wife just struggling through that thing, but really know nothing. My hypothesis is she just killed off some of the species. And we've had her tested multiple times, and who knows if the tests were accurate, but they always come back that she has very little diversity. Um and even though she's been really good about reintroducing food, she just keeps hitting limits. Given how much clinical experience you have, you colonoscopy people all day, every day. You work with people in and out. For you, what you've seen over and over and over is low and slow. You reintroduce species, you start radically increasing the variety, and the microbes are there. They've just been so underfed for so long. You're putting the gut through rehab, and they will come back. Uh so, generally speaking, yes. I do believe that to be true. But let's let's not narrow this down to like what I do for a living, where complex people your your wife Lisa comes into my office 6 years ago. Is she going to walk out after the first visit saying, "Doctor B says I need to reintroduce fiber low and slow." and go home? Absolutely not. Like, that would be ridiculous. There's so much more complexity to it, and these are people who are suffering with complex digestive issues. And sometimes I'm trying to attack other things, not just doing dietary intervention. And sometimes I'm putting the dietary intervention on hold while I work on other parts of what's happening with their gut. Tom, their digestive function is more than their microbiome. There are aspects that are really important like motility or sensitivity of the nerves. Our gut is completely carpeted with nerves. We actually have five times more nerves in our gut than we have in our spinal cord. They're constantly feeling and sensing like literally right now as we speak. And we know for a fact that people that have had a damaged gut develop something called visceral hypersensitivity. Which means that when they eat food food that other people wouldn't even react to, other people would be like, "Whatever. No big deal." That person suffers. They feel pain. And it's because the nerves are not functioning the way that we need them to. And so for me, you know, from a dietary perspective, is my strategy typically to introduce plants low and slow, try to bring them back in, try to restore diversity to their diet? Absolutely, yes, it is. But that's that is a strategy that gets invoked at certain points on that path, not necessarily right from the beginning. Okay. So, obviously fiber, you've been very clear about that. Not for everybody, it's got to be timed well, but I think people understand that one. Um what are some other ones? You've mentioned sleep, you've mentioned exercise. Like, what what's else what else is in the basics? Well, let's start with the basics. The step number one for every single patient is always the same. What are we treating? So, we need to know what we're treating if we want to effective at treating it. Otherwise, we're just throwing mud up against the wall and seeing what sticks. So, to me it's stepping it's working into that diagnostic uh tool bag to try to identify what it is that exactly is the root of their problem. Do you do fecal testing or something else? In some cases in some cases, I would argue that the three most powerful tools that I have are upper endoscopy, colonoscopy, and a CAT scan. Between those three things, I can diagnose probably 90 to 95% of the patients who come to my office. Because what I'm doing is I'm taking your history. You tell me your story. Tell me tell me what's going on. And I'm going to integrate that with what I'm seeing in these pictures and try to put the puzzle pieces together. And so for me, that's part of the powerful information is with my own eyes, you know, whether it's endoscopy, colonoscopy, or a CAT scan. I'm using my own eyes and trying to understand based upon the story that you're telling me in the clues that I'm hearing, you know, what what's the scoop here? What could be potentially causing this? Let me give a couple quick things that can be common causes of food sensitivity for people that are very reversible and they need to hear this. Number one, constipation. If you have gas and bloating, the number one cause of gas and bloating in my clinic is constipation. You could poop every day and still be constipated. You could have diarrhea How's that possible? If you don't empty. If you don't completely empty. Yep. So, So, constipation is the manifestation of symptoms when you are incompletely evacuating or inadequately evacuating. So, if you poop, but it's just a little nugget and you strain to get it out. There's a lot of people like this. I see them every day in my clinic. And they strain and they poop and they're like, "Doc, I poop every day." I'm like, "Yeah, but do you really do you really feel like it all comes out?" They go, "No, it just doesn't feel like it. Sometimes I have to poop again like 30 minutes later. That person's constipated and they're backing up. You know, you if you poop out 70% but you trap 30% that 30% is going to start compounding every single day until you have a serious constipation issue. And Tom, you could you could literally have diarrhea. And there's this thing called overflow diarrhea where the cause of diarrhea is actually constipation. The solid stuff backs up. The liquid sneaks through the cracks and the crevices and explodes out your bottom as a liquid stool. And you go to your doctor, you're saying, "I'm having diarrhea." And they say, "Take Imodium." And you make the problem worse. So, constipation with those patients, get the bowels moving. That's step one. In fact, I will not start dietary treatment on a person who's constipated until I get their bowels moving. How do you get their bowels moving without changing the diet? Many times, uh, magnesium. Magnesium can be a great first choice. So, completely natural. Most Americans actually are low in magnesium. It's not found very easily in our diet. And, um, a magnesium supplement can do, uh, wonders. Also good good for headaches, good for depression, um, good for sleep. So, a number of other benefits to magnesium. Uh, celiac disease. Celiac disease is incredibly common. And the blood test for celiac disease is often wrong. There's two ways that you can know whether or not you have celiac disease. One is to do an endoscopy and take biopsies. And the second is to do the genetic test. But celiac disease, I have diagnosed I diagnosed celiac disease three times in one day. Wow. Yeah. So, it's way more common than people realize. And the third thing is gallbladder. The gallbladder is incredibly common and it can cause pain after meals. And it's not always the classic oh, pain in the right upper quadrant radiating to your back. It could be nausea. It could be pain. One of the key questions for the gallbladder for me is you wake up in the middle of the night with pain? Cuz the gallbladder doesn't sleep. So, if you wake up in the middle of the night, that's not irritable bowel syndrome. That can be your gallbladder. Mhm. So, so anyway, you know, to me diagnosis comes first. We need to know what we're treating. And um and then, you know, I mentioned some of the tips that I or tricks that I use. One of the other things that I often do in my clinic, Tom, is um So, I talk about fiber. I'm a big believer in dietary fiber, meaning real food. But, I find dietary supplements uh fiber supplements to actually be very helpful. For people at the beginning of their journey, not the guy that's doing 600 different vegetables, I assume. I take them myself. Really? Why? I take them myself because uh So, I guess I am going to be admitting this very publicly, but like I noticed a difference in my bowel movements. Interesting. So, and I eat a very healthy be eating more vegetables? Like, I'm really surprised that given what I assume your diet is wildly diverse, obviously 100% plant. So, how is it that you need more fiber? It's It's not so much that I need grams of fiber. It's that what I'm doing is I'm supplementing the prebiotic. And the prebiotic is the food that feeds the microbes inside our gut. And I'm targeting them. I'm targeting them with basically what they need, the precursor, to create short-chain fatty acids. The um the kale, for example, is this mix of soluble and insoluble fiber, and it's embedded in the plant, and you know, that's all really good. I love that. But, when I want to target specifically the microbiome to create butyrate, acetate, and propionate, the prebiotic fiber supplement, when chosen the right one, it allows me to do that. And I see amazing benefits to my patients who um need more fiber. But Tom, I also see amazing benefits in my patients who are suffering with digestive issues and are plant-based or vegan. And doing this sometimes gives their gut the support that they need to get over the top and really improve their diet. Very interesting. Okay, so I'm definitely understanding your strategy in terms of what the talk it is, how you're making the assessment of where somebody's at and what they need to change. Now, getting into some of the dietary things that you talked about in your book or I've heard you talk about in other interviews that I found surprising. Um talk to me about um fat, specifically saturated fat. Like, I thought for sure you'd at least go to bat for coconut, but you actually threw shade at coconut. Like, I've I've heard anybody throw shade at coconut. Um what is it about saturated fat that's problematic? Well, when it comes to the microbiome specifically and and you know, let me say there's a lot that we're continuing to learn. But I of what I've seen to date when it comes to saturated fat, I have concerns about the effect that it has on our gut microbiome. And so I'll give you an example. You know, Tom, what we look for in research, what I'm looking for is not just one study that says something. I'm looking for layers of evidence coming from different perspectives that are all pointing me in the same direction. And when it comes to saturated fat and the gut microbiome, we have preclinical studies and also animal model studies that suggest that it induces dysbiosis. And the mechanism that they're pointing to is that it leads to increased release of bile. Bile to help us to process the saturated fat. And the bile actually it the dynamic within the microbiome to promote the growth of more what are called biophilic bacteria. So, an example of one of these is Bilophila wadsworthia. Bilophila wadsworthia in these studies where they look at saturated fat starts emerging, starts popping out. And Bilophila wadsworthia has been associated with increased risk of inflammatory bowel disease. There was a study that was done. This was a study actually that changed the way that I ate in 2014. It was published in the journal Nature and people can Google this. The first author, his name is Warrens David. First name Warrens, last name David. So, look up David Nature 2014, you'll find this paper. And basically what they did, Tom, these guys weren't involved in diet wars. These are scientists. They're trying to understand how the microbiome works in humans. And what they did was they set up a group of humans with two polar opposite diets. Five days of completely plant-based versus five days of completely animal-based. So, eggs, dairy, and meat. Of course, the animal-based diet, the fiber content was zero because there is no fiber in animal products. And what they saw was that number one, the microbiome changes in less than 24 hours, whatever dietary choice you make. So, literally the food that you're eating today will have an effect on your microbiome tomorrow. Can you tell people cuz you give a really crazy stat in the book about how fast the microbiome actually um has generations? I was super shocked by that. Yeah, so the microbiome turns over a new generation every 20 minutes. It's crazy. So, if you think about it, you know, three generations of humans, like going back to your great grandparents, your microbiome's doing that in an hour. In 24 hours, if you were to equate, you know, if you were to equate the microbiome uh and how it's evolving so quickly like this to human evolution, 24 hours for the microbiome would be the equivalent to going back to the pyramids for humans. That's so insane. So, and and this is why these dietary choices that we make can change things so quickly because they're folding over new generations. Boom, boom, boom. Every 20 minutes there's a new one coming. So, the waves are coming fast. Um So, in this study, Lawrence David, Nature 2014, 5 days of plants versus 5 days of animal products. And what they saw was on the plant-based diet, it they enriched the bacteria that produce short-chain fatty acids. And no surprise, you eat more fiber, you eat more plants, you get more short-chain fatty acids. They saw that. But on the flip side, what they verified for the first time in humans, which was concerning, was what they were also seeing in the preclinical studies. When you consume this animal-product-based diet, you increase the bilophila bacteria like this bilophila wadsworthia that's been associated with inflammatory bowel disease in just 5 days. There was an increase in the bilophila wadsworthia, an increase in this one called Alistipes putredinis, which has been associated with colorectal cancer, and an increase in Bacteroides that's been also associated with both inflammatory bowel disease and colorectal cancer. In 5 days. Now, that doesn't mean that in 5 days people developed inflammatory bowel. It just means that in 5 days of this diet that is devoid of fiber, you are shifting towards something that may predispose someone who has a genetic predisposition, it may put that person over the edge, and now they manifest inflammatory bowel disease. So, you know, the point from my perspective is that when we see it in the preclinical studies and the animal model studies, and then it carries into human studies, and we're seeing the same effect, boom, boom, boom. That's what has me concerned. And so, you know, the saturated fat is a much bigger topic. It's not just the microbiome. But if we're going to focus on the microbiome today, that's my concern when it comes to saturated fat. Mhm. Okay, so I want to start putting like really fine points on things so that people can walk away knowing what the ideal lifestyle looks like from your perspective. So, microbiome is involved in just immeasurable number of things in your life that you probably don't think about. Um, that you've talked about the communication back and forth. Uh, you talked about the fact that your immune system, 70% I think you said, um, is in the gut, which is utterly fascinating. Um, we need as wide a variety of plant substances as humanly possible. You've talked about sleep. Think you mentioned exercise, but I don't know that we went too deep into it. Walk me through, so so we've got those pieces now. What are some other key pieces that people should be aware of, um, other than plant-based, sleep, fiber? What are the What are the keys? Get a pet. Interesting. Didn't see that coming. Why? Yeah. Uh, because they have a microbiome, too, and we will share microbiome. We will share microbes with, uh, the people that we surround ourselves with. So, um, get a pet, love on your spouse or significant other, the people that are, um, that you share and cohabitate with. You start to share microbes, and you start to become more similar in terms of your microbiome to one another. So, but, you know, uh, perhaps the most important thing, Tom, the people that I see in my clinic, because I take care of a lot of people who have failed with other doctors. They do everything right. They eat, you know, they eat a diet that anyone would recommend. They sleep, they exercise, they meditate, they do yoga. They're still sick. If you are suffering from trauma, an abuse history, whether it was physical, sexual, emotional, psychological, if you don't directly address that issue, you will not heal your microbiome. The stress that is driven by that underlying trauma history is an open wound that persists and it festers until it is addressed. And so in my clinic, when a person feels comfortable enough with me that they trust me that to share that kind of information with me, typically it takes four or five visits, when they do that, I always know this is where we need to go next. And we focus on working on that specifically and we get them the support that they need to heal. That's interesting. The psychology of it all is definitely not something that I would have expected, you know, being in this now as long as I have. What do you see as the future of the microbiome? Is Is it going to be FMTs? Is it just fixing the diet? Um what is it? Okay. Uh so, let's talk about FMTs if if you don't mind for 3 minutes. Please. Cuz I think I think that people will be very interested in this topic. So, FMT, fecal microbiota transplant. Um basically what that means is that you are taking someone else's poop and transferring that into you. And it sounds completely How do you get it in? So, typically what we do is we'll do a colonoscopy. And during the colonoscopy, the patient who's receiving the FMT is completely asleep, not aware what's going on. It's a routine colonoscopy, but during the exam, you basically will release the fecal transplant through a syringe. Because it's a liquid, it's not like a solid poop. You're not putting solid poop into a person. It's a liquid. You spray the liquid into their colon and it sets in and it takes hold. And the history here is that this has turned into the go-to treatment for one specific infection called Clostridioides difficile, C. diff. C. diff is a nasty bug, causes diarrhea, like bloody diarrhea. And I've had patients who um lost their colon because of C. diff. And people have died. People have died of this infection. In fact, 10 years ago, there were about 30,000 people per year dying of C. diff infection. Because we didn't have a good treatment 10 years ago until we did the most radical, absurd thing and started using fecal transplant. And when we started doing fecal transplant almost every single time within 24 to 48 hours, that patient is cured. And basically what you're doing is you're restoring a balance to the microbiome. So, Tom, it gets back to an earlier point that we made which is I said we need to get away from trying to destroy everything and get back to empowering. When you do a fecal transplant you're not destroying you're restoring. You're giving a microbiome back and then that microbiome just naturally suppresses this nasty C. diff infection. And so, now it works great for infections. We are studying it for a number of different conditions. There's literally hundreds of studies ongoing right now looking at what this is going to do. Do I believe that it's going to cure Crohn's disease and ulcerative colitis? No. I thought you were going to say yes. Tell me why. No, I'm sorry. I don't want to disappoint you, but Yeah, I know. So, well, I think the the problem is this. If you do a fecal transplant, like for example, if I get a fecal transplant but I don't change my diet, then within three or four weeks, I'll be back to the old microbiome that I had before because my microbiome will start evolving to my normal diet. Right. But if you did eat the {quote} {unquote} right way that we've been talking about this episode, would somebody with Crohn's, they get the the reset, they get the FMT, and then they eat the right diet. Let's just pretend that they actually stick to it. Um would that work or is there something else going on in Crohn's that just makes it too hard? Maybe. It might work. It might work. That's If if we were to do the study, that's the way that we would have to do it. Makes sense. Okay, so when I was researching you, I started making a list of all the vegetables that I want to keep in my house now cuz you inspired me cuz you you often ask people like, "Hey, how many vegetables would you say you eat in a week?" And the honest answer for me is probably I eat a lot, like 40% of my calories, but I eat them from six things. So, what's the number that people should be eating and what are some of the cuz look, your whole thesis is diversity, diversity, diversity. But now, give me like give me some of the main players. Won't be all of them, obviously, um but you know, what are like that dozen-ish that people should really make sure they have in the fridge? Okay, so in the study that I referenced before, which was the American Gut Project, where they found the single greatest predictor was the diversity of plants, the magic number in that study was 30 different plants per week. Now, that doesn't mean that 30 is magically better than 29, and 35 would be better than 30. But we want to strive to be up in that arena, somewhere in the range of 30 per week, which sounds like a lot, but if you, you know, if you start doing things like making smoothie bowls, you could have like 12 on Monday morning in your smoothie bowl and you're already halfway there almost. So, um with regard to what specific plants, I actually had an acronym that I put into the book. It's called F goals. F goals, like F for fiber. So, F stands for fruit and fermented. G stands for greens and whole grains. O stands for omega-3 super seeds. So, I'm talking about chia, flax, and hemp. If you ever make a smoothie, put all three of them in. A stands for aromatics, meaning like the flavor foods, like garlic, onions, shallots. L stands for legumes. Legumes, great source of fiber, resistant starches, prebiotics. And then S, I had a couple things with S that I wanted to do. Um so, I really made S about sulforaphane, which is the phytochemical that is an absolute cancer crusher that you will find in broccoli sprouts. Broccoli sprouts have this very concentrated source of sulforaphane that really, really helps to prevent cancer. Uh Johns Hopkins has an actual center where this is what they study is sulforaphane and the effects on human health. But beyond sulforaphane with S, I also believe in mushrooms, so shrooms, and seaweed or sea vegetables. I you know, I think that those are opportunities where uh like sea vegetables, for example, most of us don't eat them at all. They have unique sources of fiber. They have unique nutrients. And there's potentially a lot of benefit there. Mhm. Okay, so now you've given us some specifics there. Um I'll tell you what made my list and you tell me where I'm going right and where I'm going wrong. So, uh blueberries, blackberries, carrots, I do baby carrots specifically. I don't know if that matters. Uh broccoli, kale, bok choy, collard greens, uh cucumbers, apples. Those are sort of my There's a few more Oh, celery. There's a few more that I have on the list, but, uh, am I missing any sort of obvious like powerhouses, or is, you know, baby carrots Are they going to kill me? Like, what How am I doing? Okay, so I First of all, I love all those foods. I was, you know, as you were reading them, I got particularly excited about, um, the collards. I live in Charleston, South Carolina, so I have to. And I like the bok choy. I thought that was a good one. Um, you know, what what would be missing? I mean, I realize that, you know, given the popular narrative in nutrition, these might be considered controversial by some, but I don't really consider them to be controversial. I think whole grains and legumes, to me, those are foundational foods for the gut microbiome. When I hear legumes, I think peanuts. What else is a legume? So, peas, lentils, beans, those are all qualified as a legumes. And for the person who has a sensitive gut, a great place to start can be sprouted lentils. Lentils are a little bit more gentle, and when you sprout them, they become even more gentle than that. And it literally takes two, maybe three days to sprout them, so it's easy. But, you know, whole grains and and and, uh, and legumes, Tom, when we've studied them, people who consume these foods, uh, they live longer with less heart disease and with less cancer. I mean, I I think that the evidence is very powerful in that direction. It would be so interesting to see more and more studies come out that show causation versus correlation, cuz I know a lot of these story A lot of the studies are correlative. Man, so interesting. Dude, I never thought that somebody could make a book about fiber as interesting as you made your book. This was great, dude. Um, thank you so much for coming on. Where can people connect with you and follow? Cuz one thing I love about you is if you learn something new, and you think, hey, I've updated my thinking, you don't get dogmatic about it, which I think is really, really powerful. Um how can people connect? Uh so if you want to find me, you can find me on social media on Instagram and Facebook as the gut health MD. Uh I have a website, the plantfedgut.com, with a newsletter where like a new study comes out, you want to hear the breakdown, what does Dr. B have to say about this new study? Boom, it'll be in your inbox. That's completely free. My book Fiber Fueled, um very proud of it. It came out May of last year. It was a New York Times USA Today Publishers Weekly Best Seller. Here we are and it's sold over 120,000 copies. Wow, congratulations, man. That's extraordinary. Thank you. So and um and finally I have an online course. I felt like the book was a great starting point to connect and initiate some thoughts, but really what I want is to take people deeper and help them to fully understand how to heal their unique self, no matter who you are. This is not about this is not about making every single person the same. This is about meeting you where you are and trying to get you pointed in the right direction so that you can be better. And so that's what my course is. My course is a seven-week course that has video, audio, case studies, journal clubs, live sessions with me, live Q&A's, um private Facebook group, recipes, I mean just tons of stuff, very, very immersive, complete experience. So and you can find that at my website, the plantfedgut.com. Nice. I love it. Dude, thank you so much for joining me. This was a lot of fun, it's so interesting. And guys, speaking of things that are so interesting, if you haven't already, be sure to subscribe. And until next time, my friends, be legendary. Take care. Thank you guys so much for watching and being a part of this community. If you haven't already, be sure to subscribe. You're going to get weekly videos on building a growth mindset, cultivating grit, and unlocking your full potential.