How to tell if your poop is normal and the 5 warning signs you shouldn't ignore with Dr. Trisha Pasricha

Most people think you need to poo every day to be healthy. You don’t. In this episode, we explain how to tell if your poo is normal, the warning signs you shouldn’t ignore, and the gut mistake you may be making on the toilet every day. 

Dr. Trisha Pasricha, a leading Harvard gastroenterologist, a columnist for the Washington Post and author of the book You’ve Been Pooping All Wrong, explains how your poo, gut health, and disease risk are linked, and when you should see a doctor.

Dr. Pasricha guides us through why frequency, colour, and consistency all matter, and why there is no single “normal.” You’ll learn how to spot changes that could signal disease, including early warning signs linked to cancer and long-term brain health.

Are you looking at your poo every day? And, if not, what might you notice if you did?

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Jonathan: Trisha, thank you so much for joining me today.

Trisha: It's such a pleasure to be here.

Jonathan: And I'd like to kick off with a tradition that we have at Zoe, which is start with a quick fire round of questions. You can say yes or no or if you have to, a one sentence answer.

Trisha: Oh gosh. Okay. I'll try to restrain myself.

Jonathan: Does the color of my poop matter for my health?

Trisha: Yes.

Jonathan: Can a change in the consistency of my poop be a sign of a brain disorder?

Trisha: Yes.

Jonathan: Can stressful work deadlines make you constipated?

Trisha: I wanted to say 100%. I'll just say yes.

Jonathan: Can everyone have a delightful bowel movement?

Trisha: Yes.

Jonathan: Does the feel-good hormone dopamine interact with our gut?

Trisha: Yes and yes.

Jonathan: Can using your mobile phone at the wrong time give you hemorrhoids?

Trisha: Most likely.

Jonathan: And finally, what's the biggest misconception about bowel movements?

Trisha: That you have to poop once a day or something's wrong with you.

Jonathan: It's not true.

Trisha: Not true.

Jonathan: So I'm excited to learn what mistakes I've been making on the toilet. But before we get into that, can we sort of start with the basics? Picture this, I'm in Boston today. I've just finished my burger and fries. Yeah, that seems like by far the most popular meal that I can find in any restaurant I've been in for the whole week. Take me on the journey of what happens next through my digestive system.

Trisha: Right, so that lovely burger that you're eating, and let's suppose it's got protein in it from the meat. Maybe you've thrown that little hint of iceberg lettuce on top, like just a smidge of fiber. Okay? And then you've got the bun, which is this refined carb, and then your french fries. So first thing it's gonna go down your esophagus. Your esophagus is going to undergo this motion, which is going to be true of the entirety of your digestive tract called peristalsis. And that is essentially the muscles of your gut pushing and contracting, contracting and relaxing to push that food along. And it's gonna start in the esophagus that's gonna continue in different forms all the way until it reaches the exit hatch. So it goes from the esophagus down into the stomach. It's going to become promptly acidified and your stomach is gonna start to grind up that meal. Now the protein is gonna be a little bit harder for it to break down the meat of that bun. The fiber, even though it's a small amount of fiber, that too, is gonna take a little bit longer. The bun, the french fries, those are gonna pass a little bit more quickly into the small bowel. Once things move into the small bowel, they're very small pieces. You're gonna start to absorb the nutrients and all of the good stuff. Whatever there is in this burger and fries that your body wants to have and that's gonna get absorbed and whatever you can't absorb by design and largely that's gonna be the fiber in this case. What you can't absorb is gonna keep on moving. Maybe you have seeds on that bun, maybe the seeds are gonna keep on moving, and as it does eventually it'll go from the small bowel through a part of the bowel called the ileocecal valve, and it'll push itself into the colon. And here's where something kind of magical happens. Your colon is filled with trillions of bacteria, right? And those bacteria plus the genetic material that they contain, that's called the microbiome. And the microbiome is gonna take what's reached that area and they're gonna feed upon it. They're gonna ferment it, and then they're gonna produce these, what hopefully is a beneficial short chain fatty acid or other compounds that even though the original material, the fiber itself can't be absorbed. What they produce as a result of what you fed them, that can make it into the bloodstream and it can have these local effects right there on the colon. And then eventually your microbiome, again, trillions of bacteria. They're shedding, they're dying, they're living their best life. A lot of that is gonna mush together with whatever's made its way down there, and it's gonna form this nice compact patty that Patty is formed because your colon has been sucking water out of that stool the entire time. It'll make it to the last part of your colon called the rectum. That's when you have a critical choice to make. You can decide, is this a socially appropriate moment? Do I wanna make this happen? And you can have a bowel movement, or you can fight your instincts and clench your sphincter and hold onto it. So whenever you make that decision, and sometimes your colon will really push you to make a decision quickly, you'll release it out into the free world and the digestive process will complete.

Jonathan: One of the things you talk about is gut motility in the book. Could you explain what that is? And what is a healthy bowel movement?

Trisha: So we have it in our heads that we have to poop once a day every day. And I think that the reason that myth took flight is because there actually is a certain time of day when a lot of factors come together that prime us to have a good bowel movement. So motility when we're talking about the gut refers to movement, it refers to how the gut on its own with its muscles and it's got a very thick muscle layer, is moving things in that motion all the way down from your esophagus down to your colon. And when you wake up first thing in the morning, as it turns out, that's a time of day that we're actually really primed to have a bowel movement. First of all, your colon. It's a creature of habit. It sleeps at night. It has a circadian rhythm. When you wake up the colon buzzes with activity for the first one to two hours upon waking, more so than most of the rest of your day. There are a couple of things that can get the colon to start contracting on its own again later or around that morning time, such as going for a walk. So a lot of people in the morning go for a walk outside. They take their dog out. A lot of people drink coffee in the morning. Coffee will stimulate strong contractions. And when you put all of this together, it turns out that in the morning it is a really nice time to have a bowel movement. That doesn't mean that morning time is the only or even the best time to have a bowel movement. A lot of people very commonly have another surge of activity in their colon. Those contractions, the motility ramps up after lunch and after dinner. Those are also great times to have a bowel movement. Whenever you can have a bowel movement that leans into your own physiology, meaning your colon is doing some of that work for you, it means you have to do a little bit less work. You have to bear down less hard. And the truth of the matter is that your bowel movements are determined by a little bit more than just motility. They're determined by how soft the stool is. And so sometimes I tell people, like, having one bowel movement a day is lovely, but your stool is determined by the consistency of that stool is determined by your stress. It's determined by whether you're traveling. It's determined by whether you've decided there's a safe and appropriate bathroom nearby or not. And frankly, once you start meeting your fiber goals, which is not the case for most of us here in the US, you're gonna start pooping more than once a day. And it's gonna feel weird because you might not be used to doing that. You might not have ever been told having more frequent bowel movements is actually a good thing. You might think, oh my God, I'm having two or three bowel movements a day. Do I have diarrhea? Not necessarily. If they're comfortable, if they're easy, you move on with your life and it's because you're eating a lot of fiber. I would say that's fantastic. Very healthy, and you should embrace that new you.

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Jonathan: So the competitive person in me is now thinking, so what you're saying is once a day is good, but if I'm eating really well,

Trisha: Even better.

Jonathan: Then two or three could be even better.

Trisha: Well, I think my general rule of thumb is that normal and healthy is what is comfortable for you. So it should really do two things. One, it should be comfortable, meaning you shouldn't be straining, you shouldn't be spending 20, 30 minutes in the bathroom at a time. You know, I have a lot of patients who go once a day, but they're there straining for 20, 30 minutes. To me, you're going once a day, but you're constipated. So it should be comfortable and effortless. And then two, it should happen in ways that don't interfere with your social or work life. So if for you having three bowel movements means you get to go quite easily, it doesn't bother you. Great. Three is normal. If you're somebody who says, I've had to run out of meetings because I can't control this, or I don't even wanna go out to brunch with my friends because I'm so worried about the bathroom situation, then maybe that number doesn't make sense for you. So it's really individualized. But in a way, this is a wonderful thing because it means there's a huge range of what could be normal, and you really don't have to fit into that small box to live your best life.

Jonathan: In my early twenties, I got an infection, they call it glandular fever in the UK or mononucleosis.

Trisha: Oh yeah.

Jonathan: In the US. And after that, I sort of suddenly developed all of these food intolerances that I'd never had before, and I had a whole bunch of gut symptoms associated with this. Went to see a whole set of doctors and said you're probably really stressed. You have like irritable bowel syndrome. You should avoid fiber to deal with this and sort of push me towards a diet of sort of highly refined carbohydrates to avoid all of these things. Of course.

Trisha: Yes.

Jonathan: And haven't felt any of those symptoms for years now, and they just sort of slowly disappeared on my journey with Zoe, sort of as I have transformed what I'm eating. I'm definitely one of those people who was eating almost no fiber a decade ago, and now I'm eating tons and I never would've imagined I could. Are you saying that if you're eating a lot more fiber, there just is more poo as a result?

Trisha: Well, two things. One, yeah, the volume's gonna go up because the fiber, the soluble fiber is gonna hold onto water. It's gonna be softer. So in some ways that volume's gonna be more, but also because it's not gonna necessarily form as solid a patty that you're gonna wanna hold onto, it's gonna just come out quickly, effortlessly, and more easily. It shouldn't be pure liquid. It shouldn't look like mud. I would say that maybe we swung in the wrong direction there, but it will just be easier to pass. And in fact, they've done these studies where for example, in the US you know, there's this statistic that we talk about, which is based on a survey of thousands of adults in the US who considered themselves to have normal bowel movements. And they said, okay, how often are you going? And it turns out anywhere from three times a day to once every third day would be within the range of normal. Although people still sort of believed that once a day was normal when they looked at other countries. For example, in East India where people eat a significantly higher fiber diet. Those people were going like on a median of 14 times per week, which is almost twice as much as we sort of think is normal here in the US, but it's often just a function of fiber. And there are also other factors too, right? Like exercise plays a role. Your stress certainly can play a role, though what you're describing to me sounds interesting because it could be a form of post-infectious IBS as you're describing, but there have actually been a lot of studies about bacterial infections and how those can kind of sensitize the lining of the gut in a way that can last for several years. The good news is that as it seems to have happened in your case, sometimes we see that it does get better eventually when you change your diet, when you change your lifestyle, it just takes time.

Jonathan: Could you tell us about actually looking at this poo? After it comes out, which I know is not something that in either the UK or the US, we tend to do, but I have some German friends and like you go and visit Germany, like their toilet's sort of designed so you can have a really good look. So this is clearly like a cultural difference. So if we were to like, not pretend it hadn't happened, but were to look at it, right? Is there anything around color and consistency that can tell us about our health?

Trisha: Yeah. It's funny you bring this up because I am one of those people who've always looked, even before I became a, I mean, although this probably foreshadowed what I would become, but it's like it blows my mind. It's like, how can you not look? Why would you not look? You know? But I actually think there's an important reason to look, which is that you have to know what your normal pattern looks like. You have to know what things look like on a typical week, and it may not be the same every day. Like I said, there's so many different factors, but you wanna understand what's normal for you so that when there's a change, you can recognize it quickly, you can bring it to your doctor. So I think the first step here is start looking. You know, I'm not asking you to take photos. I'm not asking you to like make a diary about it, but just get in the habit of looking. For the most part people poop within some hue, some shade of brown, and that's normal. Most commonly, the questions that like people ask me in my clinic or they slide into my dms and ask are like, well, I had this weird green poop today. I had a yellow poop. Is that normal, not normal? And context is everything. In those situations, there are times where a green poop, a little yellowish poop could be completely normal. If there's been a big change to you, like suddenly that yellowish green poop is accompanied by diarrhea, fever, pain, and then it becomes not so normal. Purple poop is a question I get. We often get these things, these compounds called anthocyanins in our diet. They're present in berries, they're pigment. You can get it in red wine. The next day, two days later, kind of depending on how quickly your bowels are moving, you might get a little purple poop because of something you ate two days ago. That wouldn't bother me so much. Beets are a classic masquerader. If you have beets, they're gonna look maroon. Everything I've said so far could be normal, sort of depending on the context. If there's other signs and symptoms, it could be more worrisome. When in doubt, run it by your doctor. When we enter the reds, maroon, like I mentioned, bright red, dark red, and even shiny black tarry kind of sticky black. That's abnormal. I want you to run that by your doctor. Even if the most common answer and the most common reason and what they think is going on is just something like hemorrhoids or a little skin tag. That's fine. Get the reassurance. Just have someone check it out, because what we don't wanna have happen is that we're missing a bigger problem that we've brushed aside as no big deal. Probably hemorrhoids. We see this all the time, and then we could miss something more important.

Jonathan: You are going from, oh, it's sort of brown, or it's got a little bit of maroon, relaxed to suddenly red or black. It's abnormal. Check it out. What are you worrying about?

Trisha: I'm worried about bleeding from something more serious, like cancer, for example. Cancer is one of those things that I would say when I did my medical training, like in medical school. It would be something that I'd worry about for an older person, fifties, sixties, seventies. I'd say, oh, we gotta make sure this is not cancer. Today in 2026, we have to make sure if you're 20s, 30s, forties, that we're not missing cancer too. It's one of those red flag symptoms, no matter your age. So we've been seeing this really worrisome trend of rising colorectal cancer cases and other kinds of cancers as well, but in my world, colorectal cancer specifically in young people, and we've been seeing that trend since the 1980s, 1990s, and it's persisting. All the while, people who are a little bit older, those cancer rates are actually declining. And the problem with younger people, and the reason why this conversation is so important, the reason why looking is so important and just knowing what your normal pattern is, is because younger people often show up a little bit late to get care. We miss this crucial window of a couple weeks, couple months where the sign, the symptom appeared, but we're waiting on it. Or maybe even they see somebody, but that person, their provider, they're not so worried about it because you're otherwise young and healthy. And that's a classic scenario that if you have symptoms like new rectal bleeding, so like the bright red, the blood, the dark, dark, you know, the black tarry stool, abdominal pain, and then most nebulously, a change in your bowel habits could be a sign that there's something off worrisome for colorectal cancer. That's really nebulous. Like a change in bowel habits could mean is it suddenly softer than it should be? Is it suddenly pencil thin? And it wasn't like that before. These are things you are not gonna really pick up on unless you're paying real close attention. And again, my goal here is not to scare anybody, but it's really just to say that sometimes there's a perfectly reasonable explanation, like oftentimes someone's stool consistency changes and we'll say, okay, you know what? It turns out you started using this artificial sweetener and we'll pinpoint that, or you're still recovering from your jet lag. That's probably it. But if we don't have a good explanation and it persists, we have to investigate it and we're not gonna investigate it unless you bring it to your doctor's attention. And I actually should mention one more color, which is clay colored, like this pale white. That's also an emergency. You should also talk to your doctor about that. That color can indicate that bilirubin is not making it into your stool. The reason we have brown stool is not because brown is like the magical color of all our food meshed together. Bilirubin comes from bile, and that's something you're producing, it's this digestive juice, and that makes your stool brown. When there's a blockage somewhere like a stone or more worrisome like a cancer, then your natural color is gonna be this really pale, weird clay color. And people, it's striking. When you see it, it like doesn't feel right.

Jonathan: Bilirubin is what?

Trisha: It is this compound in bile and bile is this juice that aids with digestion that you produce. You store it in your gallbladder and then you release it out every time you have a meal, and it kind of helps you with digestion as you go along. It's a wonderful thing, but without it, not only does your stool become really pale and weird looking, but it's a total emergency because you need that one to have appropriate digestion. But two, it tells us there's a block somewhere and often that whatever's causing that block can be an emergency.

Jonathan: Well, I'm gonna relieve you and tell you it's still brown, so that's good. So color is good. Anything else to watch out for?

Trisha: I always like to tell people that what is normal, what is healthy is what's comfortable for you. But there's this other aspect that's kind of the consistency of the stool. And in gastroenterology we look at the Bristol stool scale and you can Google that and you can see what that looks like. But it's this nice diagram that shows how firm it is and kind of at the top that's like really firm, small rabbit pebbles. And at the bottom it's very, very loose, like almost watery. This was developed in Bristol, England. It was this doctor a couple of decades ago who just went around surveying the local healthy population and asking them what their bowel habits look like, and he figured out that depending on where you are on that scale, how firm pebbly all the way down to watery, that very nicely correlated with how long it was taking that stool to travel through the colon. And that makes sense. It correlates well with motility because your colon, one of its main jobs, has several, but one is to just draw water out of that stool and back into the bloodstream. So the longer it sits there, the harder it gets. You don't have to use the Bristol stool scale, but you should know where you are in that sort of pattern. I think you wanna sit somewhere in the middle, and if you are on those extreme ends, you should also talk to your doctor and say like, what am I doing wrong here? Like, is there something I can do to get myself a little bit more soft and fluffy? Most people who have that nice, perfect sausage, that is called a Bristol four. That's kind of what everybody feels like is the ideal thing. If you really wanna have success with your bowel movements, you have to respond when your body's telling you to go. And I think we have all of these like kind of imaginary social graces where we're like, no, no. I'm at a friend's house. I could never, and we put it off. Where at work people are embarrassed to go at work. And the problem is that suppose it's 9:00 AM you're at work, you've just got to the office, you have to go. At that point in time, the cross section, the poop that you have sitting in your rectum might be that nice sausage snake-like poop, that if you were to go respond when your colon is contracting, it would come out easily, effortlessly, and you would consider yourself to have a perfectly happy relationship with your toilet. But if you push it off and you say, no, this is not a good time for me. I'm too embarrassed to use a public stall. And then you wait until it's 9:00 PM and now your colon's not contracting because you've suppressed it. You've had 12 hours for your colon to suck more water outta that stool. That's what it's going to do. This is gonna be a very different poop than it was 12 hours ago. And suddenly now you are constipated because now not only is your colon not in the mood to play, but you have to work a lot harder because now you've become a little bit more pebble like, it's gonna be a much more difficult poop to push out, which is why people who go when their body tells 'em it's time to go and people who eat a lot of fiber and makes it a little bit softer, you have more room to give and it's just easier to go. I have a 2-year-old and a 4-year-old, and luckily they eat so much fiber that like we sometimes have the other problems. But constipation in kids is such a problem, and a lot of times it's the low fiber in our diets. And oftentimes kids retain, they don't wanna go. They're nervous, they're embarrassed, you know, whatever the reason is. And that even if you have eaten the right foods, you know, that like a very nice, fluffy, plant-based diet. If you retain it, you're gonna foil yourself.

Jonathan: You talked a bit about probably having a diet that's very low in fiber. On one hand you talked to us about this social fear of like, oh, I can't go because I'm not at home or whatever. Are there any other explanations for why we seem to have this epidemic of sort of gut problems like bloating and constipation and diarrhea, and is it true that this is like worse now than it was 50 years ago?

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Trisha: I have a hunch that it is significantly worse. So I'll give you a couple of examples. So one, you know, when I talk about what it takes to have a good bowel movement, I often explain it as trying to get toothpaste out of a toothpaste tube. And you know, you mentioned motility, which is like what I call this sort of the three P framework, but that's the propulsion. So you can squeeze that tube of toothpaste and you can try to force toothpaste out. And even if that toothpaste is like a little bit hard brittle, it's like 10 years old. Like with enough force you can get it out. But ideally the pliability of that toothpaste would be really soft. That's the second p. And so you can have a, if you start to eat more fiber, then you actually don't have to generate so much force anymore, then it just comes out on its own. And that's a lovely thing. But the third P here that we often overlook is the pelvic floor. And we really don't spend that much time optimizing the pelvic floor the way we think about these other two factors. And that's like trying to push toothpaste out of a toothpaste tube without ever taking the cap off. And the pelvic floor is this set of over a dozen muscles in our pelvic floor that have to coordinate so precisely in order to have a bowel movement. And if you think about it, when you have a bowel movement, you're bearing down 'cause we're generating this Valsalva maneuver. And if I were to like try to make a Valsalva maneuver right now, like my fist would clench, you know, because you're generating this pressure, but paradoxically, your sphincters have to relax. If you think about it, this is a little bit counterintuitive and it's very common that over time people's pelvic floor starts to work against them and they sort of train their muscles inappropriately. A lot of people when they're younger in their twenties, they haven't discovered fiber yet. They haven't discovered like a plant-based. And that's, you know what, it's just how it is. And so they have to generate a lot more pressure to have a bowel movement because there's just like, they have harder stools. And if you do that over several years, you're gonna change how those muscles respond. Those muscles are gonna eventually start to paradoxically close the very muscles you need to open such that once you hit your forties, you discover how much you love kale salad. Your muscles are not the same anymore. And so even though you have this excellent, soft plush stool, it hits up against this wall. And you know, I don't know if this is at the like point of being an epidemic, but it's somewhere between one outta four and one outta three people who struggle with constipation. They've tried all these different laxatives, it's not working. The actual issue is the pelvic floor. And so this is a hugely underappreciated problem. And I do think that in terms of why things have changed now, for us, it's this combination of factors. One, our diets have totally changed in the last 50 years. We know that. Right? And it's partially ultra processed foods, like 60% of our diets in the US are coming from ultra processed foods. And it's partially an issue of like what is in those ultra processed foods, and also partially what's not in those foods. Like we're not getting whole plant-based foods as much as we used to, but also our entire position for how we're having a bowel movement is very different from how people used to poop. Thousands of years ago, we used to squat. Okay. And I say that and everyone's like, oh my God, I would never, and I get that like everyone likes to sit on this nice little porcelain throne and it's comfortable and it's easy. But actually, if you think about it, our colon is this long tube and at the end is the rectum. When we squat, we are basically stepping on a hose like picture that there's this muscle that's called the puborectalis muscle that creates this sling around the colon and it chokes it tight and makes this little kink in it. When we're sitting at this 90 degree angle like we are right now in our chairs, and that's a kind of a good thing, like when we're sitting at work, we don't wanna have this like constant call to go to the bathroom, but we sit the exact same way when we need to go and what we're doing is choking off that tube. If we were to squat, that tube would straighten up that muscle, that sling muscle would relax and it would be nice and straight. So the simplest thing you could do, of course, would be to get a stool and raise your knees above the level of your waist, and that can kind of open up that angle. Again, a lot of people aren't doing that. I don't think we have to go back to squatting. But the other thing that I think modern life has really ruined for us is our smartphones. Like, you must remember this, I remember this in my childhood, people used to have those nice little bathroom like bookshelves. You know, like there'd be this like stack of like two month old magazines, or I remember yesterday's newspaper. No one sees that anymore. That type of reading material that's like couple days old. It's like, you know, like the sports section from a game that you've already like watched. You're not gonna get that engrossed, like it's just gonna distract you. You're gonna relax and then you'd go about doing your business. In our smartphone era, and this is something that my lab studied, we are bringing in these devices that we know from decades of other areas of science will hijack our brains and distract us for much longer than we think we have control over. Like we know this is the case for sleeping, but we're all bringing our smartphones to the bathroom. So we did this study at Beth Israel where we looked at people who were coming in for their screening colonoscopy. So these are people 45 and older, and we asked them a bunch of questions about their smartphone use. Do you bring your smartphone to the bathroom? What do you do on the smartphone when you're in there? And then we also asked them about diet and other habits that we know are part of their bowel habits. And then we did their colonoscopies. We took a look. We visualized, do you have hemorrhoids? Do you not have hemorrhoids? And it turns out in this population, the majority of people are bringing their smartphones in there. That's probably not a huge surprise, but the people who brought their smartphones in, just bringing your smartphone into the bathroom was associated with a 46% increased risk of having hemorrhoids.

Jonathan: 46%.

Trisha: That's not a joke. That's a big number right there. And we accounted for things like how much fiber they were taking in, how much they exercise, how much they sat at work, all of these other factors that in constipation, how much they strained. Those are traditional risk factors for hemorrhoids. But it turns out just this seemed to increase their risk independently. And again, this is a study that looked at an association. It didn't prove causation. But what we think is happening is that when you bring your smartphone into the bathroom and you're sitting on this open toilet bowl where there's no pelvic floor support. So you start to have this passive pressure that's filling up the vein. So hemorrhoids are just veins. They're just cushions of veins that eventually they fill, they become engorged enlarged, and then we notice them. We notice them as a problem, but they've kind of been there the whole time, and they sit in your anal canal. And when they become engorged, we call them hemorrhoids, and they become a problem. So when you're sitting in that open bowl without any kind of counter pressure, over time, you do that for weeks to even years and you know, people are using their smartphone from the, like, you know, like the day they were born, that connective tissue will weaken and those veins will fill. And we think that's why it puts you at increased risk of hemorrhoids.

Jonathan: Because you have the phone. Are you just sitting on the toilet longer? Is that what you're saying is happening as a result of the smartphone? Is that what's causing the

Trisha: Yeah, you're so distracted. And so we asked this in our survey. We said, okay, how often, or how many of you are sitting there in your toilet longer than you intended because of the smartphone? So not only did we find that people who brought their smartphone in, even if they had equivalent amounts of constipation between the non-smartphone user, the smartphone users, they were five times as likely to spend more than five minutes in the bathroom, and about half of them said, yeah, I'm consciously aware I'm spending more time in there than I intended to. I tell people, try not to spend more than five minutes.

Jonathan: I'd like to move on now to the brain gut connection.

Trisha: Yes.

Jonathan: Because I think you've done a wonderful job of talking us through the gut. What is the link between the brain and the bowels?

Trisha: So, neurogastroenterology, which is my field, and that's the study of the gut brain connection. It has been around only for the last, you know, formally in the last 30 years. But we've known about the connection for much longer, for more than a century. Even back in the 1890s, a lot of us in high school, we learned about Ivan Pavlov and his experiment with conditioning, classical conditioning, where he would, apparently it was a bell, he would ring a bell and he would associate that with bringing food in for his dogs. And eventually just the sound of ringing the bell would cause the dogs to believe that food was on its way. And he observed that they started to salivate. And then it came to be that like, you know, he could just, he could just ring the bell even without bringing food in, and they would salivate, and that was the conditioning. But if you think about this from a neurogastroenterological perspective, which is how I think about it, the even more interesting finding there is that the first phase of digestion doesn't start when you chew food. It doesn't start when it hits the stomach. It starts when you think about food, it begins in your brain and just thinking about food, like right now. I love pasta. If I were to picture this like nice steaming bowl of cheesy fettuccine Alfredo, and I'm like lifting the fork and the cheese is going down, like I could start salivating thinking about this.

Jonathan: You're making me hungry right now.

Trisha: Oh, I know this is like the wrong time. But if you think about that, what other organ do we have where just our thoughts can change their function? Right? Like no matter how much I think about gushing waterfalls. I'm not actually making my kidneys filter blood more quickly and put more urine into my bladder at best. Maybe doing that, I could get the bladder to like relax and squeeze, but the kidneys are gonna do what they're gonna do regardless. Our lungs are taking air in, whether I'm thinking about the mountainside or my Boston commute this morning at the same rate. But the gut is very different. So researchers have known that there's been this close connection for a long time and for most of the last a hundred years until the 1990s or so. The way we thought about the gut brain connection was that it's the brain calling the shots like our thoughts, and then our mental health issues, our anxiety, our depression, our stress, those can cause changes to our gut, and we know that to be true. We live that experience almost every week, every month, every day, even when we're nervous. When you're excited because you're on a date and you get butterflies in your stomach, that is a feeling and a thought and an emotion that's causing a real change in your gut. And this is something that I've studied and what we know is happening is that when we have these kinds of emotions, excitement, fear, anxiety, a hormone called corticotropin releasing hormone is released by the brain and it causes the stomach to come to a grinding halt. The stomach has this kind of baseline motion where it's contracting at three cycles per minute 'cause it's kind of just sweeping things along at all times. That goes into a chaotic rhythm when we're stressed and that sort of stops things from moving forward. But at the same time, your colon, the very last part of that colon starts to ramp up with activity. And so that's also why a lot of times when people are stressed, they feel, yeah, they feel nauseated from their stomach, not really moving. And it might feel like you have this like sudden sinking pit in the bottom of your stomach, but they also feel like, oh my God, I have to go to the bathroom. Why do I have to, like, right before, you know, you're like going on for some theater performance. This happened to me in high school. I'd be like, why right now? Do I have to go? I didn't feel this way 10 minutes ago. Well, it's that, that's the reaction.

Jonathan: That's your brain sending these signals to your gut saying you need to go,

Trisha: You gotta go, and it changes your motility. And one way that it does that is this hormone and a lot of the communication is this main highway between the brain and the gut called the vagus nerve. The vagus nerve is this long nerve that starts up in your brain, and it extends down through not just the gut, but it innervates the heart, it innervates the lungs, all these other major organs. And that's an important way that the brain can very quickly communicate with the gut. But by the time we reach the 1990s, a very interesting shift happened where people start to say, wait a minute. 90% of the signaling from the vagus nerve is not actually going from the brain to the gut. It's going from the gut up to the brain.

Jonathan: So it's actually going in the opposite direction. And you would think from our, like everything starts in the brain.

Trisha: Yes, yes. We live in this brain centric world and actually, our gut is calling the shots in a very different language than I think we've like sort of experienced or believed for most of our lives. And the gut, as it turns out, has a brain of its own. And that's what I think, like my main mission as a neurogastroenterologist is to get people to understand is that there is a brain that's living in your gut. It's called the enteric nervous system, right? The brain in your head is called the central nervous system, where we have this enteric nervous system. And that actually a lot of organs had, well before they had a brain in their heads, right? Like the jellyfish, picture a jellyfish, it's like this cute little floating, translucent dude you can see right through his head. And there's no brain, right? But somehow it's out there. It's making decisions about where to get food. It's deciding what it's gonna eat. It's all because it has this network of nerve cells throughout its tentacles called the enteric nervous system that's helping it make that decision. There were some really landmark studies that were done in the nineties and then two thousands that basically flipped this paradigm about how stress impacts the gut on its head. So, you know, IBS, Irritable Bowel Syndrome is one of probably the most common diagnoses in all of GI, not just my world, but it is one that neurogastroenterologists see a lot. And the most common thing I hear from my patients who come to me is that for most of their lives, they were told it's all in my head. My gut symptoms were due to stress. It sounds like you got told that too at some point.

Jonathan: Absolutely.

Trisha: Yeah, and I think that's not necessarily intended to be as dismissive as it is, but it's because of this several hundred years of like, that's how we framed it in medicine and that was based on real studies that showed that connection to be true. And they started to do this series of very elegant experiments in the two thousands where they said, okay. We know in IBS that there are high rates of anxiety and depression, and we also know one of the big risk factors for IBS is trauma, especially childhood trauma. The kind of trauma that we have when our nervous systems are still in their infancy can really have an outsize impact in who we become as adults. We know that. So they said, okay, let's do these experiments in rats. They said, okay, we'll take one group of rats and they're gonna experience a little bit of emotional trauma. They'll separate them from the moms for a short period of time. Then they took a second group of rats and they said, let's irritate the guts with just like a mild acid, like a, like almost like vinegar, and then there's a control group. They did none of those things, and then after a couple days, those rats all grew up and became adults. They socialized the same way, had the same environment. Well, what they found was that the ones who had been separated from their moms for just a brief period at birth, they experienced pain in their guts to small amounts of distension that the control group didn't even feel like they inserted a small balloon and distended it, and the control group didn't even know that a balloon was being inserted. They just like kind of went about their business. That group that had experienced emotional trauma felt it. And what's sort of the hallmark of irritable bowel syndrome is that we know that the nerves in the gut have a lower threshold to be triggered, that those nerves are sending pain signals up to the brain for signals that other people who don't have IBS would just perceive as normal. Those are things like, you know, food passing through, gas passing through those shouldn't cause pain, but they do when you have irritable bowel syndrome. And that was measurable.

Jonathan: You started off by explaining to me that it's almost like I've got a brain in my gut.

Trisha: Yeah.

Jonathan: What do we now understand?

Trisha: It turns out from this experiment and several others that followed, and then they looked at epidemiological studies in humans, that trauma to the gut, to that brain and the gut can actually be what causes the anxiety later in your life, the depression later in your life. And then once you have anxiety, once you're sort of hypervigilant about the pain that you're feeling, of course that can, we know that causes a feedback loop down to the gut again, and it can form this vicious cycle where these things feed off of each other. Importantly, if we took a step back in a lot of cases with IBS, the disorders that we would consider brain disorders, they actually started first in the gut. And we're seeing that not just in IBS, but now in my laboratory, we're studying Parkinson's disease. And often when you know, like a lot of the response I get is like, what, you're a gastroenterologist. Why aren't there you studying Parkinson's disease? And it's because just like so many other diseases that we once framed as being primarily a problem of the brain in your head, we're learning that they start in the gut. They start early in the gut and Parkinson's. There's this whole hypothesis that's now very well supported by the evidence that at least for a subset of patients, that misfolded protein called alpha-synuclein, which is the hallmark of Parkinson's disease. We think it starts to misfold first in the gut, decades before it reaches the.

Jonathan: Trisha, for people who aren't familiar with Parkinson's disease, could you give us a very simple understanding of what that is? Yeah. And also why it's so surprising that that might start as a gut disease.

Trisha: Yeah. Parkinson's disease is a disease that we typically think of affecting people who are a little bit older. In their sixties, seventies, eighties, and often how it manifests is with tremors and difficulties with movement. They might have rigidity of their muscles, difficulty walking and tremors, and then there's a whole host of other complications that can go with it. And that's sort of how we thought about Parkinson's for several decades. And we know that certain risk factors for Parkinson's, like for example in America where people play football and they get head injuries and concussions, that can certainly put you at increased risk of Parkinson's and what we know also to be true is that there's this protein called alpha-synuclein that misfolds, and when it misfolds, it seems to be involved in why these particular dopamine neurons die and they die in a part of the brain responsible for movement. And so that's why we think they get the tremors in rigidity. But later on in the nineties and two thousands, they started to do these studies where they looked at autopsies of people who had Parkinson's disease, but they looked at their guts instead of looking at their brains, and it turns out their guts were riddled with this misfolded alpha-synuclein protein. 80% of people with Parkinson's disease have some GI issue, constipation, nausea, trouble swallowing. It's so severe, and it turns out having constipation early in life is a predictor of Parkinson's disease later.

Jonathan: So if you have constipation earlier, that's just, you're more likely to get Parkinson's later.

Trisha: Yeah. And again, constipation, just to be so clear, incredibly common in our society. So everyone who has constipation is not gonna get Parkinson's disease, but it is associated with a pretty significant increased risk. And especially when people start to say, oh yeah, I have constipation, and someone, this is someone in their forties, maybe 50, like a little bit earlier than you would think of necessarily off the bat for Parkinson's. But if they say, I have constipation, this is new. Maybe they have a family history of Parkinson's, or they say, I've lost my sense of smell, or I'm having trouble sleeping. There are all these other signs that are not necessarily directly related to their brain, per se, and the tremors that you might say, wait, this is starting to form a more suspicious picture for Parkinson's.

Jonathan: Trisha, are you saying that Parkinson's disease actually starts as something, as a disease in your gut before anything is happening in your brain?

Trisha: Yeah, that's absolutely right. We think that for a subset of patients, there's some trigger that occurs in the gut first, and maybe that trigger is an infection. Maybe it's something in the environment like a chemical that you might've ingested. I know a lot of people have thought and have studied the pesticides in the foods that we eat as being a risk factor. In my labs, we study ulcers and erosions and damage to the mucosal lining, and we found that people who had damage to their mucosal lining, these would be from things like too much NSAIDs. These are nonsteroidal anti-inflammatory drugs like ibuprofen that can damage a lining. Those people have a 76% increased risk of going on to develop Parkinson's later in life. So we know that there's these possible triggers. We haven't worked out all of the mechanisms yet, but triggers that begin in the gut. And the idea is that as that protein starts to misfold because of that trigger, it travels from the enteric nervous system up and ascends the vagus nerve, and eventually it reaches the brain. And what's exciting about this from a research standpoint is that because this process is happening years, if not decades before it hits the brain, there's an opportunity to potentially try to identify it and stop it before we get there, and that's sort of the long-term goal of all of our research programs here.

Jonathan: You're describing this very direct link between a disease that's actually starting in the gut. You're now saying, and ends up having these very severe brain symptoms with Parkinson's, and you've talked about the fact there's all of this amazing talk. Yeah. Through this vagus nerve between like my gut and my brain. Is there any evidence that your gut is shaping these other things that we think of as being the brain, whether depression, anxiety, things like this.

Trisha: There's very good data that anxiety and depression are influenced by the brain in your gut, by your gut. They can start in your gut, but even be molded by your gut. There's also data in earlier stages than in Parkinson's disease about Alzheimer's, so some of these symptoms too about constipation being a predictor for developing Parkinson's disease. They saw a similar pattern for Alzheimer's dementia as well. And actually, interestingly, the pathway that I described about alpha-synuclein protein misfolding and traveling up the vagus nerve in Parkinson's disease is actually very well understood, in some aspects we have an even poorer understanding in Alzheimer's, but how these two things are linked. But we know that there seems to be a strong association there. We know that there's an association there between GI symptoms and autism, for example, which typically has been thought of as a disorder that lives in the brain. But you know, if you know anyone with autism or you treat patients with them as I do, they have very severe GI symptoms. And of course the question is why, and what is causing what? And I think there's a lot in the literature that is now pointing towards, it's the brain and the gut that is starting and feeding some of these issues.

Jonathan: So I think it's amazing, and I think you are painting a picture almost where I may have thought previously, like my brain and my gut are completely separate, and now you're saying like they are deeply interlinked. And weirdly there's a lot more conversation going from my gut to my brain, in fact, than in the opposite direction. So I would love to take all of this and now start to talk about practical strategies for our listeners. Maybe just start with like, what does it mean to poop? Right.

Trisha: Well, I think the first and foremost thing is to listen to your body and not to treat pooping like some big shameful entity. People put off pooping or they're embarrassed to talk about with a provider, and they're gonna miss an opportunity to just have an easy, effortless bowel movement when they do that. So the very first step is to just not feel embarrassed about it. You know, like if you're at a friend's house. That's when you have to go, just go for goodness sakes. That's one thing. Then I think people need to think about their posture, change their posture, think about their diet, and change their diet. All of these things contribute to how you are having a healthy, safe, socially appropriate bowel movement. I think some of the biggest and hardest things about our own lives change is our diet and having a healthy bowel movement is partially yes, ramping up fiber, like we always talk about fiber. And certainly like we're not meeting our fiber goals for the most part, a lot of us. And that's about 25 grams for women and 38 grams for men. You wanna do two more things. One is you wanna eat a diversity of plants and you wanna not eat the exact same thing every single day, three times a day. And then the next layer. And I think this is like the harder part for people to get on board with, like, at least in America, is fermented foods. Fermented foods are this way of adding probiotics to your diet and into your body naturally. Right. And we can talk about, like, some people think like, well, I should take a probiotic supplement. And some people find a benefit from those. But the data's really stronger when we get these things from our diet. You know, there was this great study that I'm sure you know, from Stanford, from Justin Sonnenburg's team where he asked a bunch of typical Americans who probably don't eat that much fermented foods like Greek yogurt, like kimchi, like sauerkraut. And he just said like, ramp it up as best you can. Eat as many as you can in a day. And that was the group. And then there was another group that didn't do that, but both were eating like a pretty good diet. Otherwise, like these were people who were eating high fiber, the ones who did that, but then also ramped up their fermented foods. Their gut diversity changed within a matter of about two to three months. Once you have more diversity, that's sort of one of the classical markers of a healthy microbiome overall, and it means that they're producing those microbes or producing more of the anti-inflammatory compounds you want.

Jonathan: What would be the go-to plants that you would be suggesting to someone who is constipated and is looking to try and solve that.

Trisha: Yeah. I love a leafy green vegetable. Peas are actually what I feed my kids. Like we've never had an issue with constipation because they're cute, they like eating one pea at a time, but like peas are not for the weak and they have a lot of fiber in them. Brussels sprouts, broccoli's good, cruciferous vegetables are good, but it doesn't have to all be a leafy green vegetable. Don't live this life of kale salads, which is not for everybody. If you are suffering with constipation, a lot of us will have grandmothers who said, oh, well you should take our prunes. And prunes are great for constipation, like they actually do. They've done these great studies head-to-head with prunes and then a fiber supplement called psyllium and they found actually yeah, prunes are wonderful, but was right. But what more recent studies have shown randomized controlled trials are kiwis. Two kiwis a day can be great when you're specifically dealing with bloating and constipation. And yes, they're very high in fiber, but probably it's more than just the fiber because these studies that have compared head-to-head randomized control trials of kiwis and prunes. They've sort of balanced so that you're getting the same amount of fiber from both groups. But the kiwis seem to do a better job, cause less bloating. And we think it's because when you eat these different kinds of fruits and vegetables and whole grains and other things, you're getting more than just the fiber. You're getting all of the other nutrients that come with these foods. And so we actually don't know quite what the mechanism is about kiwis, but we do know it's beneficial. So like a quick trick if you're really struggling with constipation is kiwis or prunes. Prunes can make people's bloating a little bit worse. Kiwis didn't seem to do that.

Jonathan: Is there anything else other than the food we eat that we could be doing that is going to support this gut motility and reduce constipation?

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Trisha: Yeah, the two other factors that I think we don't think about for our guts, we think about them probably more often for our brain health or for other organs, are exercise and sleep. Well, it turns out those are incredibly important for our guts as well. Regular exercise, like the kind you do long-term sustain, it becomes a habit that's associated with increased motility of your gut, which will give you an easier, more quickly passing stool in the long term. If you just go for a walk once in the morning, just that movement alone will start to stimulate contractions. We have big holiday dinners around Christmas or Thanksgiving or whatever the big holiday, Easter's coming up. You might say, you know, after a big family meal like that, what I really wanna do is lie down on the couch. And it turns out that even just sitting upright allows intestinal gas and contents to move about 30, 33% more effectively than lying down. So really, our bodies are not primed to be like in this prone position, or even ideally sitting down in a desk chair like we do all day. We know that's not great for our heart health. We know that's not necessarily great for our brains, but it's actually not great for your guts either. And then sleep having a predictable rhythm. Like I mentioned, your gut operates on a circadian rhythm. It will respond to the patterns that you've set. So if you sleep at different times. You wake up at different times. Some days you eat breakfast, some days you don't. All of this will feel like chaos to your colon. Your colon wants to sleep at the same time, wake up and get these predictable cues of like, okay, we're gonna have coffee in the morning and I'm gonna have a nice, large meal that's gonna stretch my stomach a little bit, and that stretch is gonna cause a reflex that'll make my colon contract. And if you don't do those things predictably, it'll be harder for you because you then have to do the work that your colon's not doing. But the flip side of this, which is great news for people of constipation, is that you can train your colon, like your colon can be trained into developing a new pattern, developing those responses to the external cues in your environment that you're gonna give it.

Jonathan: Let's say I'm thinking about this also in terms of saying, well, I would like to keep my brain function as well as possible, and maybe what I wanna do is try and minimize anxiety and depression. So lift mood and energy. Is there anything out of, you know, your research that suggests what you would want to do?

Trisha: So a lot of my patients will come in and they'll say, I'm feeling stressed, like I'm having an anxiety attack. And that's when I feel these like horrible knots in my stomach. What do I do in those moments? And that's sort of the acute issue and what I tell them to do in those moments is tapping into the vagus nerve. Because the vagus nerve, when it starts to ramp up, it starts to slow things down. So that colon that's rapidly emptying and moving and saying, we're having a problem. If you tap into the vagus nerve, it kind of just relaxes a little bit. So sometimes I think if you're having this like acute moment of crisis, doing something as simple as box breathing, which is like where you take a deep breath in 1, 2, 3, 4, and then you hold it 1, 2, 3, 4. Then you exhale 1, 2, 3, 4, and you're drawing a box and then you hold it 1, 2, 3, 4. If you do that three times, that can stimulate the vagus nerve. And yes, you calm down, like your heart rate will slow down, but your gut will actually relax a little bit too. So I think that's a helpful maneuver. If I could pick just one thing, it would be to eat fewer ultra processed foods. And the reason is that ultra processed foods are crowding out our opportunity to eat whole foods and we found that there's certainly a link between mood and ultra processed foods. There's a strong connection between irritable bowel syndrome and ultra processed foods such that in studies when people cut down those ultra processed foods, their IBS symptoms get better. And with it we know go hand in hand a lot of these mental health issues, the more you're eating whole foods, the more you're incorporating fruits and vegetables and whole grains and these things into your diet, the better your mood's gonna be because that's really strongly supported by the epidemiological studies.

Jonathan: I would love to do a quick summary, if that's all right, and just correct me if I get anything wrong and I just focus maybe on things that really spring to mind. The first thing, which is like strongest is if you bring your mobile phone into the toilet with you, you have a 46% higher chance of getting hemorrhoids, which is pretty stunning. So I think the message is don't, or at least don't switch it on until you're finished and you've put the toilet seat back down. Second thing is, it's a myth to say that you have to poo once a day to be healthy. In fact, if you're eating like a really healthy diet and it's gonna have lots of fiber and you might even be going two or three times a day and there's not a problem with that. Yep. The key is like, is it comfortable, is it effortless? And you know, have you got, I love this, a Bristol four sausage was I think, is your description the dream? Yeah. Almost sounds like something you would buy in the supermarket, but you probably wouldn't want to. You do want to look at it. Yes. 'Cause color matters every day. And you know if it's red or black, actually you should go and talk to your doctor. Yeah. And you are saying particularly think about that if maybe you're younger and you just assume that, of course there can't be any problems because there is this rising rates of cancer, and this is one of the ways that you can see what's going on in a place otherwise you wouldn't know anything about. Then we talked about this connection between the brain and the gut and this amazing fact that this comes from the research that you are doing in your lab. You know, Parkinson's isn't really a brain disease. It's actually a gut disease that ends up having these terrible brain symptoms, and it could well be because we now understand there's a very strong link between our gut and our brain that things like Alzheimer's may also very much be influenced by things that are going on in our guts much earlier, but this is not yet proven. This is still like a hypothesis, but I see you nodding, so you're clearly like, this seems really interesting. And then I think we talked about the fact that like one in three people struggle with constipation, and that's obviously a huge number. It's related to the sort of food that we're eating and we talked about, you know, what do you need to do? And I think the one thing that comes through all the way through this conversation is fiber, which is another way of talking about plants and all these things that we don't have. We touched on the fact that you really wanna reduce your ultra processed food as well. It's implicated in so many of the things that you talked about. Interestingly, I thought there were a number of things that you talked about that weren't obvious. So for example, you said like your colon has its own body clock, so it goes to sleep at night. Yeah. It wakes up. So you really wanna have this pattern. If you have a good pattern, it's just gonna make it easier. And if you're constantly saying, no, now isn't a good time, you're actually going to create these challenges. And if you are constipated, clearly eating lots of plants, you talked about, I think 30 grams of fiber. You had a couple of specific tricks, which I loved. Prunes is definitely what my grandmother said, but apparently there's an upgraded offer. Two kiwis a day has the same effect, avoids bloating, and then things you might be surprised about. Think about exercise and sleep as well. So it's not just about diet, it's also about the other things you can do that will support you.

Trisha: Yes, the perfect summary.