What's the Deal with Poop?

Perry: [00:00:00] Before we get started today, a quick correction on our tic episode. Hat tip to Parker Hudson. Infectious disease doctor. Um and, uh, hospital, University of Pennsylvania alumnus like me who pointed out that the, uh, International Infectious Disease Society only recommends prophylactic antibiotics for prevention of Lyme disease for high risk tick bites. Um, which means that it's an Ixodes species tick. So like a deer tick that you live in a highly endemic area and that it was attached for more than 36 hours. Otherwise, the ID society says just watch and wait.

Emily: [00:00:37] Perry, do men take longer to poop than women?

Perry: [00:00:42] I have no idea. Do they do I?

Emily: [00:00:47] Uh, well, yes. Fun fact.

Perry: [00:00:49] Because I'm browsing my phone.

Emily: [00:00:51] All mammals pretty much poop in about 12 seconds. So actually, it doesn't take very long to poop. But [00:01:00] the data does suggest that men spend more time in the bathroom, and one time, a men's magazine did a highly, highly scientific survey of what was happening in there, and it was that they were reading on their phone.

Perry: [00:01:15] Oh, is that what they said?

Emily: [00:01:17] That is what they said. Yes.

Perry: [00:01:19] Fine. Yes, everyone. That's what we're doing. I have a I have my copy of Wittgenstein Right by the toilet, and I like to get a few chapters in in peace. Sorry. Not sorry.

Emily: [00:01:31] 12 seconds. 12 seconds is what you get.

Perry: [00:01:34] Oh. All right. Well, I have poop inferiority complex already. As we start our now two episodes in a row. We've done ticks now. Poop. Sort of like an ick themed.

Emily: [00:01:45] I could not be more excited. I do not think people talk enough about their poop and I can't wait to discuss more about it.

Perry: [00:01:51] I'm good. I'm glad you're poop positive. Um, I am poop skeptical, but I hope that after this episode, we'll all be more comfortable with that [00:02:00] most natural of human bodily functions.

Emily: [00:02:06] I'm Emily Oster, I'm an economist and a data expert.

Perry: [00:02:09] And I'm Perry Wilson. I'm a medical doctor.

Emily: [00:02:11] It's Thursday, September 3rd, 2026. And this is Wellness, Actually.

Perry: [00:02:16] Because you're getting a staggering amount of health and wellness information nowadays from every source imaginable. And some of it is awesome.

Emily: [00:02:25] And some of it is, well, actually bullshit. Fortunately, we're both people who know how to read studies, how to parse the data, and can tell you what's worth thinking about and what you can safely ignore.

Perry: [00:02:38] But before we dig in a note that this podcast is for educational purposes and should not be construed as medical advice. We don't know your unique situation, so talk to your doctor for personal health decisions.

Emily: [00:02:50] This week we're asking what's the deal with poop? Perry and I will give the official smash or pass, and then we'll get to your question of the week. But first, let's do the health news roundup after the break. [00:03:00] And now for the health news of the week. The first thing I wanted to talk about was rabies. Rabies is completely terrifying. It's one of the things I am the most afraid of. And it now seems like maybe it's underreported. Say more.

Perry: [00:03:26] Yeah, yeah. Rabies is super scary because it is a disease without a cure that's uniformly fatal. That's what everyone needs to know. If you need to know anything besides that, you need to know that rabies has a rather long latent period between the bite or even like people have been scratched and contracted rabies and the time it manifests with symptoms. When you hit symptoms, it's basically over. But if you get vaccinated after the bite, but before symptoms develop. You can almost always be protected from rabies, so that's [00:04:00] what people need to know. Rabies is very uncommon, though. From 2000 to 2024, there were 60 reported cases in the US. 59 of those were fatal. The one exception is a woman named Gianna Geese in 2004 who underwent this, um, special protocol, was in an induced coma for a very long time, but I just checked up. She's living a normal life now. Sort of a miracle. She's like the only rabies survivor. Um, fascinating story, but a new study just came out in Nature Communications that says that those 60 cases is a fairly dramatic undercount. They estimate, in fact, that there have been 856 cases of rabies over that time period. And the way they are estimating that is what's kind of interesting about this study and actually pertains to my neck of the woods, because every once in a while, when you transplant an organ into a new person.

Perry: [00:04:53] That organ has a disease that you didn't test for. You didn't know it had. And of course, then you put that organ like a [00:05:00] terrible example would be like HIV. I mean, obviously we test for HIV, but there have been rare cases where tests have been false negatives or whatever. And like you transplant that organ into someone, not only do you transplant the infected organ, but you're immunosuppressing the recipient because they're getting a transplant. It's a, it's a perfect storm, really, for these infections to crop up. And there have been three instances of undiagnosed rabies in a brain dead donor, which only came to light after that brain dead donor had their organs transplanted into other people. There was one most recently in February 2025, where the exposure was the donor had been scratched by a skunk. Okay, so what the researchers did is they were like, okay, we know how many deceased donors there have been over this time period. There have been 239,251. We know that three of them had rabies that we weren't aware of. And if you scale that up to the if you assume that their rate of rabies is the same as, [00:06:00] you know, the general population, then we scale that to 239,000 up to the general population.

Perry: [00:06:05] We get 856 cases. The idea here being that every once in a while people come in and like how this would manifest is as an encephalitis, a brain infection that, you know, person comes in and if you don't test for rabies, you might not know it's rabies, right? You would just say, oh my gosh, they have some horrible encephalitis. You do a bunch of tests, but you know, maybe you don't hear a story about an animal exposure, right? Like that's the problem people, you know, a bat was flying around their house. They don't even know they were bitten or something like that. The person invariably dies because they have symptoms. Rabies is uniformly fatal. And, you know, you go to transplant their organs. Or in the case of the people that that don't go on to donate, they just they just die and it gets listed as encephalitis. It's not actually easy to test for rabies. You have to send the test to the CDC or certain state labs can do it, but generally your hospital can't do it. So you need to kind of be aware of it. And so yeah, we [00:07:00] might be missing. I mean, it's still not many, but might be missing more rabies cases than we are aware of. And maybe people should be aware of it.

Emily: [00:07:08] I do think people should be aware. I will say I want to like dial down the the I want to like, just.

Perry: [00:07:14] Dial it up, dial it up.

Emily: [00:07:16] Not I want to dial.

Perry: [00:07:17] It down.

Emily: [00:07:19] Because this is still not that many cases and it is still really something you can do something about. So if there is a bat in your house, it is. Even if you do not know that you were bitten by. It is worth discussing with your doctor whether you should get a rabies vaccine. It's not that bad. One time we found a dead bat in a guest house that we were staying in, and my entire family got like the full on rabies situation. And you know, that's a giant needle, but it was totally fine.

Perry: [00:07:50] Yeah. Yeah. And it's not just bats. Any mammal, really. Any mammal. Very small mammals usually die before they can bite you. So like mice and stuff like that. But certainly skunks, I think possums [00:08:00] famously are like, don't get rabies. But still, any strangely behaving mammal that you have an interaction with is something to be worried about. And as we say, you know, you put this off and once those symptoms start and it might be weeks, it might even be a couple of months after exposure, it's over. So yeah.

Emily: [00:08:18] Okay.

Perry: [00:08:18] Scary. All right. Um, Emily, you know, I debated whether I wanted to put this on the list, but there's been so much talk about the measles deaths in Pennsylvania that I think we just have to weigh in here. So why don't you walk me through what's going on with measles writ large? And why is there so much consternation over these two? Perhaps measles related, perhaps measles associated deaths in Lancaster County.

Emily: [00:08:50] So I think it's important to start by setting the stage that we have had more measles this year than in many, many, many, many previous years. [00:09:00] Uh, the we've had 2777 so far this year. It's the most since the early 1990s. The previous record since then was set last year, and there was a week in January of 2026 when there were more measles cases in that week than in most of the previous 20 years for the whole year. So we are.

Perry: [00:09:20] Contagious. We said that a couple of times.

Emily: [00:09:23] It's really contagious, and so we are clearly seeing more measles. And that is not a there is no debate about that. There is also no debate about the fact that measles can kill you. So depending on the population that you're looking at estimates of mortality or something like 1 in 1000, some of that mortality is actually Longer term. So measles has impacts on your immune system that can cause death in in later. For kids who have had it, they may die later. So measles is definitely more around. It is also a potentially fatal disease. Most people don't die of measles. So most people, I [00:10:00] mean, most people don't die of measles, but also most people who get measles don't die of it. Right? So those things are all true. We are now having an argument about two particular cases of deaths in Pennsylvania that may or may not have been associated with measles. And part of what's hard about this is that sometimes when people die of things they don't, it's not actually that obvious precisely what they died of. And, you know, for example, when people die of of HIV or Aids, they are typically dying of something else. You know, there's a cancer, there's something else that affected their immune system. But the underlying cause is this the HIV virus.

Emily: [00:10:42] In this particular case, there are two measles associated deaths. One of them I think we know almost nothing about. The other is a baby. And it's pretty clear now actually what happened. The Atlantic did some amazing reporting on this, where they went and they talked to the family. What happened is the mom [00:11:00] and some of the other children in the family had very serious measles cases. Shortly after that, the mom gave birth. The baby had a lacerated spleen, which is not a very common, not a very common thing that happened, but can happen potentially as a result of maternal measles infection. The baby died and that's what happened. And so it's kind of ambiguous whether you want to say that's because of measles or not. It's not because a three month old baby got infected with measles and then died of measles. It's not that straightforward. It also seems very likely that the serious measles infection in Mom was a factor in the death. And the reality is that there is a baby that died. And that is extremely sad. And these facts I said about measles are true at the beginning. And this whole thing is so political in a way that is [00:12:00] very frustrating from a public health standpoint.

Perry: [00:12:03] Yeah, it's it's ghoulish. Right? You know, we're picking through these little tidbits of information that you get and you don't have adequate information. You know, a lacerated spleen, as you say, is incredibly rare. It can happen through birth trauma. It can also happen because of spleen enlargement, which can happen from measles. Now the coroner was like, well, the spleen was enlarged. But actually if it's bleeding, it can be hard to tell if the spleen was enlarged because it kind of deflates if it's bleeding. And so you have to weigh it. And we don't know the weight of the spleen. Like we could go on and on and on. And in the end, this mom was sick enough to be in the hospital. I mean, it does appear like this was a preterm birth. We still don't know whether it was a like what the whether it was a C-section or vaginal delivery. Like, honestly, at this point, I'm like, okay, you know, the unambiguous fact is that we're doing a poor job controlling an ongoing and growing measles outbreak.

Emily: [00:12:56] That's it. That's the whole thing.

Perry: [00:12:57] And, and this is not like [00:13:00] the early days of Covid when we're like, oh, what do we do? Like, how do we stop this? Do we isolate? Do we mask? Like, do we try hydrochloroquine all these things? We've known how to do this for decades and decades and decades. It requires vaccination because measles is so infectious, it requires a lot of vaccination to achieve something like herd immunity. And the broad, you know, RFK Jr and other administration officials will pay lip service to being like, oh, I'm not anti-vax, I'm not anti-vax. But then, you know, kicking up a firestorm like this seems just like it almost feels like they're looking for an excuse to say, oh, no, you know, don't worry. Right. Measles is not a big deal. So it's okay if you're not getting vaccinated and you know whether or not these kids would have died had they not had measles, this counterfactual that is impossible to test. It's still bad. There's other things that can happen. Measles [00:14:00] can cause encephalitis. Measles cause secondary pneumonia, missed school. Measles can cause this immune memory loss where it makes you more susceptible to other infections for years afterwards. It's just not good. And we have a solution. It just is like, seems like we're cutting off our nose to spite our face here.

Emily: [00:14:16] It's very frustrating. And, uh, also very sad. And I'm not sure how much there is to say about this.

Perry: [00:14:23] The one thing I will say I'll always have one more thing to say is just because people might be wondering that newborns can't get the MMR vaccine. I mean, one of the reasons that we worry about measles outbreaks is that because the MMR is a live attenuated vaccine, there are a lot of people who can't get it, including babies, until they're nine months old, and then people who are immunocompromised, who have transplants and things like that, which is why herd immunity might be important to protect them. Obviously, the mother could have gotten vaccinated at some point. Generally, we don't recommend vaccination during pregnancy.

Emily: [00:14:57] Sorry. Can I correct can I correct something, please?

Perry: [00:14:59] Yeah. [00:15:00]

Emily: [00:15:00] So the the reason we do not vaccinate newborns for measles is because they will not develop immunity until sometime after the maternal immunity wears off. So they have some immunity from their mom for about the first six months, sometime between 6 and 12 months. That wears off. But if you vaccinate them before that, it doesn't actually prompt their own immunity. So you can give your infant a measles vaccine as early as six months. Then you need another dose at 12 months and another dose more than three months after that. So. Excellent. There are some ways to protect the baby, and very small infants are generally protected to some extent by their mothers. Mmr titers.

Perry: [00:15:36] Very nice. Thank you. Appreciate that. Um all right. Let's move on. That is it for the health news of the week. Um, now for something completely different. Uh, Emily, what's the deal with poop?

Emily: [00:15:53] I am so excited to talk about it.Uh, so I thought a lot.About how we should help people understand this [00:16:00] and what is really the, the kind of question here. And I think I want to frame the question as like, is poop a window to your soul? You know, we like how much can we learn about ourselves by our poop? And in the US, we're not really that into talking about like, people don't like to talk about it. But that's not true in every culture. Some cultures are much more into discussing like the details of their of their poop.

Perry: [00:16:25] And my, my wife is Jewish. I don't know if you're including that as a culture, but, um. Yeah.

Emily: [00:16:32] It's discussed.

Perry: [00:16:34] It is discussed.

Emily: [00:16:36] So this whole episode, I think we should think of that frame. We're going to ask, is poop a window to your soul? And how much can we learn from your from your poop?

Perry: [00:16:46] I love it. All right. Talk to me.

Emily: [00:16:49] No, you talk to me. You're the doctor. Let's start with science. Tell me, what is my poop?

Perry: [00:16:55] Oh, okay. That I can answer. I can't, I can't answer whether it's part of your soul, but I can tell [00:17:00] you what's in it. Um. Okay, so this is what's poop. It's water of differing amounts, depending on how much is reabsorbed by your colon. It is sloughed, sloughed, sloughed epithelial cells. So sort of the lining of your colon as the poop passes through. It's a bunch of fiber from the food that you eat and can't digest. And then it is bacterial biomass. And you may wonder about the color and the smell. There's some interesting science here. So it is generally brown because of something called stercobilin which is bilirubin metabolite. So this actually comes from the heme in your red blood cells that gets as red blood cells get broken down in your body. The heme which is iron containing, gets released. And that gets metabolized into bilirubin and other things that comes out in your stool and has a brownish color. We'll talk later about maybe what colors of stool are something to be alarmed about. [00:18:00] And then there's the smell, the odor, which is there. You know, some of that is hydrogen sulfide, the same smell that you get from rotten eggs, which comes from bacterial metabolism. But actually a fun, fun fact. Part of the smell is a bacterial product called Skatole, which is gives a particularly characteristic human poop smell and little known fact. Skatole is a somewhat popular additive to perfumes because in very small amounts it apparently has a bit of a florally musk scent to it. And yet another example of the dose makes the poison coming you from the Wellness Actually podcast.

Emily: [00:18:48] That's kind of gross, actually. I find that gross. Okay. Um, all right, so that's proof positive. Oh, we're gonna be positive.

Perry: [00:18:56] Okay, I did look it up. I did look it up. The skatole that is in your perfume is [00:19:00] not harvested directly from poop.

Emily: [00:19:03] That is.

Perry: [00:19:04] Synthesized in a, in a lab.

Emily: [00:19:06] Cool. Okay. Um. All right. So that's what it is. I think the core question people have before we get to the window of for the soul is like, is my poop, uh, is my poop regular? And this is, I think, part of why we should talk about why we should talk about poop. Because people wonder if they're pooping is like other people's pooping and you don't know. Um, okay, so a few things in the Nhanes data. Everybody's favorite nationally representative survey of Americans. They ask people many things, including how often they poop and they kind of.

Perry: [00:19:41] Do you ever wonder about the Nhanes people when they're getting together for like next year's survey? And they're like, all right, guys, what we did, we did alcohol intake. We did, um, you know, blood pressure and someone like someone sheepishly, like raises their, raises their hand. It's like, um, all right. Anyway, go ahead.

Emily: [00:19:59] What does [00:20:00] the Nhanes so much? Um, so, uh, so in that data, the sort of typical range is something like three times a day, up to three times a week. And the modal person is pooping once a day. I actually think these numbers are a little bit misleading in the sense that, like, almost everyone is in that range, including people who are having issues with their pooping. So frequency is actually not a very good discriminator about whether you are sick or you're, you're healthy. So like if you're pooping 15 times a day, you probably are spending all of your time in the bathroom. That's like a signal of a problem. If you're pooping less than three times a week, that is also likely a signal of constipation, but there's a pretty wide range, and you could be having issues with your digestive system even within that range.

Perry: [00:20:48] Right? Most people, even with, uh, like irritable bowel syndrome or, um, inflammatory bowel disease, uh, you know, like significant GI problems still fall within [00:21:00] that range. So it's not actually that helpful. Like there's as much variation between people. What I think people don't talk about. Well, let's talk about consistency because we have to talk about the Bristol stool.

Emily: [00:21:11] Bristol stool scale.

Perry: [00:21:12] Bristol Stool scale. The good people at Bristol have created a qualitative Fail to judge what your stool looks like, and it ranges from type one, which is described as separate hard lumps, like little pebbles. I think like rabbit poop or something like that, all the way to type seven, which is watery with no solid pieces. Those are both abnormal. The sort of standard recommended I don't recommend it. Healthy ish Bristol Stool chart are types three and four. Type three is described as sausage shaped with cracks on the surface, and type four is thinner and more snake like, plus smooth and soft. So that's what we're looking for, consistency wise. And [00:22:00] most of this is driven by water absorption which happens along the colon. Your colon reabsorbs a lot of the water from your stool. And it does that based on the transit time of passage. So like the longer stool sits in there, the more water gets sucked up and the drier and harder and lumpier it gets. And we don't talk about transit time.

Emily: [00:22:25] But transit time is interesting because it varies quite a lot. Something normal transit times are something like 10 to 75 hours. And that's actually huge. I mean, that's a huge.

Perry: [00:22:36] And that is that's mouth to toilet transit time.

Emily: [00:22:39] Mouth to toilet transit time. And you can test mouth to toilet transit time by, uh, there's actually two ways. So, uh, so a free way to do it is, is to eat corn. So most people cannot digest, uh, like a lot of corn kernels. So if you eat a corn on the cob and then you wait to see when you see the corn kernels in your poop, that's [00:23:00] a good, good metric. Uh, you can also dye your poop blue. So there's different commercial and other frosting related ways to do this.

Perry: [00:23:09] You can do this accidentally.

Emily: [00:23:11] You can do this accidentally. And that's fun. That's like a fun activity.

Perry: [00:23:15] I want to. Can we play a clip? Because this is getting like the blue poop challenge is an Instagram thing. Let me yeah, let me play that for you.

Influencer: [00:23:22] Have you done the blue poo test? The purpose of this test is to see how fast the food that you eat goes through you. So you make blue colored muffins. You eat two of them for breakfast, and then you wait to see how long it takes for your poo to turn blue. This will tell you your transit time. Most people should be aiming for between 14 to 50 ish hours of transit time. If it takes you longer to see blue poo in the toilet, it might be a sign that you're constipated or that your digestion needs some work. A big contributor to pelvic floor dysfunction is constipation, and optimizing the transit time is one part of improving your gut health and eliminating [00:24:00] constipation.

Perry: [00:24:02] Um, so this is something you, you, you can do in the, in the, in the comforts of your own home. Um, what kind of food coloring to add? I've seen online, um, royal blue food coloring, right? You want to die like a muffin or something like that. And the normal transit time, as you said, is between 10 to 75 hours. So ten would be sort of the short end and 75 would be the long end of time between eating a blue muffin and seeing some blue or maybe greenish or some abnormal color coming out the other end.

Emily: [00:24:36] Now, having said that, like transiting your poop very quickly is not like a like a life goal, right? This idea that like we are trying to like poop max and get our, like, get our optimal frequency and like have the laxatives or the poop gets out fast. Like that's not a thing you need to, to do. So very long transit times can be associated with constipation because [00:25:00] the water gets pulled out and pulled out. And so that's like something to be aware of. But, uh, you shouldn't be trying to take the blue poop challenge and then like optimize. So the poop comes out as fast as possible. That's not that's not just not healthy.

Perry: [00:25:15] No, I mean, too fast would lead to malabsorption. And, you know, you want to digest your food. Like that's part of that's, that's everything, right?

Emily: [00:25:24] Um, if you're using it for.

Perry: [00:25:26] You know, if you read online, people say, oh, transit time within this normal 10 to 75 hour range has not been sort of associated with any particularly bad outcome. So it's nothing you need to worry about much. But when we get into like the microbiology of poop, like the different types of bacteria are in there, what we find is actually a lot of that variation is driven by transit time. So I'm going to table that for a minute as we talk about the so that when we talk about the fecal microbiome, we can remember that transit time is a thing. [00:26:00] And maybe knowing your transit time, maybe it doesn't give you any life goal in terms of making it shorter or longer or whatever, but is nevertheless interesting information from sort of a scientific and physiologic standpoint. And it's fun.

Emily: [00:26:13] Okay. Before we get into all of that, I think it's worth saying, what are the things that would make you worry about your poop? Like, what are the things to be concerned about if it's not transit times or, uh, or frequency? So one is if there is blood, blood in the stool always deserves a call to your doctor. I will say that fun fact about 40% of serious runners have blood in their stool. Sometimes it's very, very common after like a hard effort after a marathon. Yeah. Because when you're working really hard for a long period of time, your body basically pulls like everything it can out of the gut, like your digestion just totally flakes apart. Okay. And then you have bloody diarrhea after, [00:27:00] uh, and it is bright red blood. Like just looks like what you'd be very worried about.

Perry: [00:27:06] Okay. Can we do an episode on, like, people, humans shouldn't run marathons. This is. I'm going to. I'm hot. Take. The first guy who did it died.

Emily: [00:27:15] Died. That's true. But he wasn't. He wasn't feeling adequately. So I think that's something to think about, what with the new carb options. Um, anyway, different episode, but I will say, even if you are a serious runner, if you are pooping blood, you should tell your doctor about that and you can decide what what to do. Okay. Uh, your poop shouldn't be black unless you are taking a lot of iron, which will turn it black and it shouldn't be pale. That can be a sign of a problem with your gallbladder. Is that right?

Perry: [00:27:43] Yeah. I mean, pale poop is pretty scary. Uh, gallbladder obstruction, which could hopefully be a gallstone in the common bile duct, but more ominously, could be a sign of cancer that's obstructing the common bile duct, which we don't love. So definitely get that checked out.

Emily: [00:27:58] Uh, the other thing is just weight loss and [00:28:00] unexplained changes in pooping. Those are the those are potential symptoms of a serious issue. And people generally should not routinely poop at night. So in the middle of the night, pooping. Sometimes it happens, but it's not a typical way your body would digest. And if that's a regular thing, that's also worth a worth a call.

Perry: [00:28:20] Yeah, we talked about this in a prior episode, but I think that pooping is this amazing example of the brain gut axis because your like social environment cues you to poop like, like we've talked about how, you know, for a lot of people, it's like they don't feel like they've got to go and then they get home where it's like, oh, my nice toilet and everything. And then it's like, oh, now I have to go. Right? Like that's your brain telling your gut like, let's go. Now's the time. Coffee does this too. So caffeine obviously can stimulate your colon, but actually decaffeinated coffee prompts people to poop as well. And that's probably just a learned behavior. And your brain talks [00:29:00] to your gut, which is why sleeping you generally like your brain, knows that it's not. You shouldn't be pooping in your sleep. So if you are, talk to a doctor.

Emily: [00:29:08] Okay, so that is what your poop tells you on a basic like what you can observe in the toilet. The two other big pooping questions for me are what can change your poop? So if you do find yourself in a bad part of the Bristol Stool scale, like in the rabbit poop era of your Bristol stool, like, what can you do to fix it? And then I want to talk about the microbiome because it's very hot right now and people are totally into it and they want to they want to know about it. So we're going to do both of those things. But before that, let's take a quick break. Okay. We're back and I want to talk about fiber mixing. Perry, are you fiber mixing?

Perry: [00:29:49] Oh, so no, we already did protein mixing. I'm too focused on protein to focus on.

Emily: [00:29:57] Sorry. You got to do both. You got to do both. And [00:30:00] none of them are in this, like, cheese powder that you eat all the time. So you're in trouble.

Perry: [00:30:04] I had my do I have it here? No, I had my I had my protein drink, my oikos 30g of protein, whey protein milkshake, which has no fiber. I'm actually concerned about our lack of fiber given our protein maxing stuff. Emily, I have no evidence that this is true, but I'm going to assert it without evidence. Only here on the Wellness Actually podcast will you hear the hosts admit that there's something completely without evidence. But I believe that fiber. I have some evidence for this. Fiber might be the nutrient that Americans are subtherapeutic like missing the recommended value on more than any other nutrient, right? Like, like protein. We talked about protein and the, the recommended protein intake, which is quite low because it's just the amount you need not to like waste away to nothing. Like almost every American is getting more than that. And then we argue that probably they should be [00:31:00] getting more. But even the recommended amount of fiber, which is like 20 to 25g a day, according to Nhanes, the mean US fiber intake is 17g a day. So like most Americans are like below actually the recommended fiber intake. So we're bad at this at fiber maxing.

Emily: [00:31:20] I don't find that very surprising, actually, because it's not that easy to add fiber to stuff. Like most of the things we do in processing food, take fiber out of it, and just putting it back in is like not as easy as just making stuff with protein. I think.

Perry: [00:31:40] Oh my God, what a good definition for ultra processed foods. Not the like official definition by any stretch, but, but like taking the fiber out to make everything easier to eat and digest.

Emily: [00:31:51] Yeah, high energy density, but fiber comes actually in two types. It comes in soluble and insoluble fiber and also fermentable and not so I guess there's [00:32:00] like a two by two box of this. So soluble fiber is like it gels, it's like oatmeal, like gels things together in your stomach. And it slows the process of things through your, through your gut. Insoluble fiber is like, um, like wheat bran and, or, you know, any kind of, uh, like a husk, any type of husk of things. Yeah. And that's like nature's broom. I think that's what people think about more. It's sort of like flushes it all out. Um, and that's the stuff you see, uh, in whole form in your poop a lot of the time.

Perry: [00:32:34] Yeah. And this explains why doctors will recommend fiber both for constipation and for diarrhea. Um, and they'll often not go into detail about like which fiber they're talking about, but it's that insoluble fiber, cellulose, wheat bran and stuff like that that is just going to transit right through. Those are non-fermenting, which means they don't cause gas formation, which a lot of people don't like when they are taking in fiber, right? So you like looking [00:33:00] for a non-fermentable insoluble fiber is kind of going to clean you out without causing too much gas. That's good for constipation. A soluble non-fermenting fiber is actually going to slow things down. So when you're having kind of loose stools and you want to bulk up your stools, that's something like psyllium would be a prototypical supplement there that doesn't cause gas. And then we have all the fermentable fibers, like, like resistant starch and all the things on the Fodmap diet that we talked about a few episodes ago, which are which are good sources of fiber, but the bacteria in your gut will ferment them and that generates gas. And then you have farts, which maybe that can be our next episode just totally fine. Let's keep going.

Emily: [00:33:41] So what's the.

Perry: [00:33:42] Deal with farting?

Emily: [00:33:44] What's the deal? Uh, good sources of fiber include beans. Beans have a lot of fiber. Chia seeds have a lot of fiber. Oatmeal has a good amount of, uh, of soluble fiber. So there are a lot of ways to get fiber, but they [00:34:00] mostly are in the form of whole foods and fruits and vegetables.

Perry: [00:34:05] Yeah. You got to eat your fruits and vegetables, kids. We, you know, you see a lot of health claims about the benefits of fiber beyond like it'll keep you regular. And I think there's a fair amount of support for this. I anticipate Emily is not going to be as gung ho as I am, but she's already rolling her eyes. All right. I have strong observational data from multiple studies that higher fiber intake can reduce the risk of cardiovascular disease and stroke, as well as reduce. I'm using causal language, which you're going to yell at me for. Higher fiber intake is associated with a lower risk of colon cancer as well. Um, Emily, you're going to say I predict that, well, people who eat a lot of fiber do a lot of other healthy things. And that's why they are healthier in the long term.

Emily: [00:34:57] That's what I'm going to say. And randomized trial data [00:35:00] has actually not supported some of these colon cancer claims.

Perry: [00:35:03] That's a very hard trial to do because we're talking about fiber intake for 20 years.

Emily: [00:35:07] I agree, I agree this is a hard question to answer. And I think part of my issue with this literature is your people say, oh, this is such a strong set of things because we have this Lancet paper and it's 135 million person years. But the thing is that when you add data, but it has all of the same biases, you haven't fixed your causal versus correlation problem. You've just made your correlations more precise. We have a very it's very, very clear that more fiber is associated with good health outcomes, but that is very different from saying that it is a causal link. And I don't think the causal evidence there is especially good. And we don't need to revisit my feelings on this in every episode. Although we could. We should.

Perry: [00:35:54] I like it makes me feel like I'm coming home to, you know, a nice a nice warm [00:36:00] sofa.

Emily: [00:36:01] Not even any Mendelian randomization in this one. So, you.

Perry: [00:36:03] Know, oh, well, if there was, I would use causal language.

Speaker 5: [00:36:05] Bummer.

Perry: [00:36:06] Just a really piss you off.

Speaker 5: [00:36:08] The last thing I wanted to say.

Emily: [00:36:09] About fiber is that you actually do need hydration to make your poop work with your fiber, but more hydration isn't more helpful. So fiber tends to be like when you add it, your poop gets better. You need to be adequately hydrated to appropriately poop because as your poop moves through your colon, uh, pulls water out. And if you don't have enough water, it will like prioritize pulling the water out for other bodily functions and then leave your poop all dry and bristle. Type one rabbit pellets. But just drinking and drinking and drinking and drinking and being like, way more hydrated than you need to be is not going to make your poop nice. I don't know.

Perry: [00:36:47] All right, get my water bottle with me.

Emily: [00:36:49] All right. Wait, I want to say two more things about how you poop. How people poop. Good.

Perry: [00:36:54] Oh, yeah. Yeah, yeah. Besides fiber, there's more than fiber.

Emily: [00:36:56] There's more than fiber. Uh, one thing is the Squatty potty. Do you [00:37:00] have a squatty potty?

Perry: [00:37:01] No, I don't, and.

Emily: [00:37:02] Oh, my God, you're missing. What is wrong with you?

Perry: [00:37:04] I know. Well, I didn't know the data. And then I did the research, and now I'm like, I don't know, squatty Potty.

Emily: [00:37:11] Squatty potty is great. So the Squatty Potty is just a thing that you put under. It's like a piece of it's like a plastic stool and you put it around the your toilet and you put your feet up on it and it changes like your posture basically puts your knees up and it makes your, uh, your, your colon, like, I don't know, straighter or whatever. It's more mimicking a squatting posture, which is the way people pooped before we got toilets. And there's randomized data, actually randomized crossover data where they have people poop in both, in both ways. Uh, and this improves the sense of complete emptying by like three times and it reduces the straining by a lot. Um, and this is very cheap and the effect sizes are big and I really, really think [00:38:00] that you should get one.

Perry: [00:38:02] Do you have one?

Emily: [00:38:04] Absolutely. We have multiple. I have them on like all of my toilets. I'm not an idiot. Yes.

Perry: [00:38:09] Um. I'm an idiot. Uh, I, I, I want to file this. So. Okay, so I was seeing some crazy stuff online of, okay, this is gross, but people being like, if you're really poop maxing, you shouldn't have to wipe. Okay. Like, and that's gross. First of all, that's gross. Um, but one of the arguments is like, animals don't wipe. And that is, that is true. It's not.

Emily: [00:38:35] I used to have this cat that didn't wipe and it always had poop all over its butt. So like, I am just like not getting into this.

Perry: [00:38:41] One of the things though, so like why I do these deep dives for this podcast. I don't know, it shows that something's deeply wrong with me, but I went to a little bit of evolutionary biology. And it turns out that, um, one of the reasons we have to wipe is because we walk erect. It's, it's like we can add it [00:39:00] to the checklist of things that because we evolved to walk erect, which gave us, you know, use of our hands for tools. That was very nice. Um, and maybe like seeing over some high grasses in the African savanna or whatever else it was. We condemned ourselves to like a life of back pain, um, a birth canal that is all jacked up and high maternal mortality and the need to wipe our poops. And apparently there's evidence that humans have been wiping their poop since like before civilizations, before we had paper, before we had anything. So it's not like that animals are doing something right and we're doing something wrong. It's we, we should never have stood up in the first place. And maybe the Squatty Potty corrects that just a little bit.

Emily: [00:39:43] I'm not really sure that's what the Squatty Potty does. And you still have to. You still have to, uh, you.

Perry: [00:39:48] Know, keep wiping people.

Emily: [00:39:50] You keep wiping people don't stop wiping. Um, but you get.

Perry: [00:39:54] One of those, um, bidet like, uh, seats on my toilet, which is a total game changer. [00:40:00] I will say I love it.

Emily: [00:40:01] Okay. Um, the other thing is you should not use your phone on the toilet because it encourages you to sit for too long. That is.

Perry: [00:40:11] Insane. You're you're crazy.

Emily: [00:40:14] I realize this is a stupid thing to say, and many of us use our phone on the toilet all the time, and I don't. But it is, I think, a different way to say this is there have been some studies associated with that show that people use their phone. You just sit for too long. So using your phone briefly on the toilet is fine. But if you're just like sitting and sitting because you're trying to avoid your family and scrolling on your phone on the toilet, you should get off the toilet and sit in a different part of the bathroom and pretend that you're on the toilet, because otherwise you're going to get hemorrhoids.

Perry: [00:40:43] Um, yeah, I saw that study and I think it's right, but it is very hard. I, I will say if I like, forget my phone, like if I leave my phone in another room and I'm on the toilet, I am desperate. Like I will grab a shampoo bottle and read the ingredients.

Emily: [00:40:57] I can't be alone with yourself. What does [00:41:00] that tell us? Barry?

Perry: [00:41:01] I cannot do it. I, I can't just sit quietly with my thoughts or.

Emily: [00:41:06] For like the 12 seconds that it should take you to. Actually, you know what would be better if you get a squatty potty, be going faster, and then you wouldn't be so bored.

Perry: [00:41:14] All right, squatty potty hooked me up.

Emily: [00:41:18] Okay, so knees up, phones down, eat your fiber, drink some water, have some coffee. That's like the practical stuff, but the more like fun, sexy piece of this is the is the microbiome and the idea that this exciting constellation of bacteria and fungi that are living in us are really important for a lot of things. I feel like the microbiome had like a big moment, like a couple of years ago. And now I kind of like the every episode of The Economist had a thing about the microbiome. And I feel like it's like died out a little bit.

Perry: [00:41:56] In the medical side. It's still like, oh.

Emily: [00:41:58] You.

Perry: [00:41:58] Guys are.

Emily: [00:41:58] Still really into it.

Perry: [00:41:59] Oh, okay. [00:42:00] Great.

Emily: [00:42:00] Excellent. Uh, so what, what, what is this? And why are we thinking about it? Why do we care?

Perry: [00:42:06] Um, okay, so everyone knows there's bacteria in your stool, but, like, it's more than just there's bacteria. It is an ecosystem. There are thousands of types of different species of bacteria that live in your gut, that live in your colon. They're all interacting with each other. They're digesting food for you. They're releasing substances that are absorbed into your body. Without them, we would be very sick. Like these are these are symbiotes that live within us. Um, people often ask like, you'll hear statistics, like how much bacteria do you have in your colon with like, I have £10 of bacteria. That's not true. You have 0.2kg worth of bacteria in your colon. That's about an apple's worth of bacteria. But that's still a lot because bacteria are very small. So the way [00:43:00] most microbiome studies work is you take a stool sample that is sent to a lab under varying conditions. There are some problems with these studies, but um, and it's mixed up and labs will do DNA sequencing for a bunch of different known bacteria. So every bacteria has a short sequence of DNA that's kind of unique to it.

Perry: [00:43:19] And it's just like, okay, if we find this sequence of DNA, we can therefore infer that this particular bacteria was in the stool. And you do that for a bunch of different hundreds or even thousands of different bacteria. And you can see, uh, the relative amounts of bacteria in someone's stool. And basically everyone has about 14 genuses. There are the same 14 genuses of bacteria that sort of like the human stool microbiome, but that like vastly underestimates the amount of diversity from person to person. So in a study of 4000 people looking at their stool microbiome, 75%. So 3000 of those 4000 [00:44:00] had at least one bacteria type that was not found in any other person. So the chances are you have a bacteria living in your colon that at least you know in your town, there is no one else who has that particular bacteria. And that's seems nice. That's super cool. That's nice. Right? I feel like I would want to know my personal bacteria a little bit better and like, uh, talk to it, see how it's like in life.

Emily: [00:44:28] So people's microbiome is in that sense, quite person specific. So actually, like you can identify. Even a year later, people have shown like you can basically re-identify like 80% of people a year later by various like aspects of their, of their microbiome. Having said that, there's actually quite a lot of individual over time variation within an individual in your microbiome. So it's not like you have one kind and exactly the same number of bacteria all the time. It's [00:45:00] moving around with various aspects of your life.

Perry: [00:45:02] It's moving around a ton, and I don't think people appreciate the amount of within person variation. So for example, you know, a lot of the wellness microbiome, uh, uh, influencers will talk about certain species of bacteria and, you know, the relative abundance of something like akkermansia or whatever, like your akkermansia is too low. You need to take this supplement that I happen to sell to boost your akkermansia. And like any individual bacteria, might vary in terms of concentration by tenfold between one day and the next day. So it's like it's very different saying taking the entire sum of bacteria, we can re-identify you from a data set, sort of like, oh, everyone has kind of unique fingerprints then to say, oh, the particular world's on your fingerprint are like causing health or disease, right? Like the, the fact that many people are surprised at is there is no reference microbiome.

Emily: [00:45:59] There's [00:46:00] no good. Yeah. I mean, this is the thing about people like make your microbiome great. By what? Like what, what, how would I know if it was great?

Perry: [00:46:09] Who is the.

Emily: [00:46:10] Guy?

Perry: [00:46:10] Who are we aspiring?

Emily: [00:46:12] The person with the best microbiome? Like, what is Brian Johnson? I mean, we probably do know what Brian Johnson's microbiome is, but like, is that something to aspire to? Like, I don't know how there is no optimal here, the way there might be in some other things that we might, uh, that we might measure.

Perry: [00:46:29] Yeah. Micro, uh, what's his name? Brian Johnson's microbiome is probably screwed up because he has autoimmune gastritis. So I don't think their microbiome. Yeah. So these things are shifting around a lot. It is unique to you the primary driver. I mean, you know, people will tell you, oh, it's you know what you're eating and you're healthy lifestyle behaviors. It's going to change your flora and fauna inside your, your gut, the primary driver in all of these studies that does repeat testing, right? So the same person, like what is causing [00:47:00] change here is callback transit time. That seems to be the thing that changes your microbiome. And that makes biologic sense because the longer stool is sitting in there, the more oxygen is getting taken up by aerobic bacteria. So the oxygen levels are going down. And then the anaerobic bacteria, the bacteria that don't need oxygen to grow, start growing sort of later in the process. And so there's these dynamic shifts. There is some associational data that a greater percentage of anaerobic bacteria are associated with some worse health outcomes than aerobic bacteria. That might argue that shorter transit times would be better. Or maybe it argues that having a diet that promotes short transit times is healthy.

Emily: [00:47:54] Because it has a lot of fiber in it.

Perry: [00:47:56] Right? And the and the bacteria are just sort of like a side effect that are kind of [00:48:00] moving around based on that exposure.

Emily: [00:48:02] So this for me is like the core issue with this microbiome stuff, which is like, it's, it is crystal clear that the microbiome varies across people and that it is, it plays a role in our lives, right? Like, and we can talk about this in a second, but like, you know, getting rid of your microbiome would be an extremely bad idea. We definitely are using that. But that is totally different from saying like, this is a thing where changing it, even if you knew how to do that, would necessarily have some positive health outcome or knowing more in more detail, like how would I change it? And what, what would I want to achieve? And that could be different for different people. That's the other thing. It could be like my optimal microbiome is different from your optimal microbiome.

Perry: [00:48:47] Totally.

Emily: [00:48:48] Certainly that's true.

Perry: [00:48:49] Yeah. We know that's well, do we know that? I guess we don't know what optimal microbiome is. So I don't know. But I even want to hammer home one more time that we don't really know whether the readout [00:49:00] of bacteria in your poop is a result of your health, or that the bacteria in your poop are causing health changes. So for example, like, let's just talk about what you'll hear when it comes to microbiome. So you'll hear that there's a, I'll sometimes call it a dysbiosis pattern, right? So no researcher worth their salt is going to tell you that any one type of bacteria in your stool is good or bad. I mean, obviously if you have like salmonella, that's bad, but you know what I mean. Like they're not going to tell you that like, oh, this particular you want this higher, this lower, whatever. But they will use very complicated statistical techniques to identify patterns. And they found patterns that are associated with things like inflammatory bowel disease, colon cancer, obesity, and other metabolic diseases. To me, a common thread in this dysbiosis pattern is that inflammation in the colon leads to decreased oxygen tension, which leads to increased anaerobic [00:50:00] bacteria. So I can tell a story where you have inflammatory bowel disease for some other reason, cause inflammation. That inflammation changes your gut bacteria. We read that out of your poop. Fine. Gut bacteria, nothing to do with it. They're just there enjoying the environment in which they live, the anaerobic environment in which they live. Here's another story that's consistent with that data. For whatever reason, you got colonized with more anaerobic bacteria because I don't know, you've eaten wrong and you didn't get your, you know, enough fiber or whatever. Those bacteria release substances that angry up your colon, which then becomes inflamed and give you, gives you inflammatory bowel disease. That's the state of observational data right now. And the only way to sort of figure out causality here is to do fairly dramatic things, to try to change the microbiome in a human and see like, does it change their health?

Emily: [00:50:52] And, and this is a place where I think the, the start of some of this microbiome is based on a [00:51:00] really, really compelling set of very specific data. So there's a condition called C diff, which is a very debilitating diarrheal disease, uh, that people can get. And it's like a recurrent persistent infection that it can be really, you know, again, sort of really terrible. And it, it turns out, uh, that fecal transplants, transplanting healthy stool into the colon of somebody who has this is incredibly effective at treating this like much, much, much more effective, like 80 to 90% resolution versus standard antibiotics, which have a pretty low effect. This is like, this is the way that you treat this disease now effectively.

Perry: [00:51:49] Yeah. Recurrent C diff, you know, and this makes sense because C diff Clostridium difficile can colonize your gut when the other bacteria in your gut are killed. Like most people get this after [00:52:00] taking a course of antibiotics, it's often a hospital acquired infections. You get antibiotics that kills off all your quote unquote good bacteria in your gut. C diff takes over and you need to get those good bacteria back. And healthy stool has those good bacteria in it. So yeah, fecal microbiota transplant pretty awesome endorsed by every major society for recurrent C diff.

Emily: [00:52:20] And this has been explored then in treatment of similar things like IBS, which they have a little more mixed ulcerative colitis, but places where it seems like there's something going wrong in the sort of stool transit system that might be impacted by changing the the bacteria. All of this other shit that people tell you, though, this is actually not supported. So there's this sort of idea like, okay, well, if taking someone with a really serious illness and putting somebody else's poop in them, uh, is going to fix that illness, then maybe you would just generally get healthier if you took some capsules of bacteria, but like [00:53:00] those are not the same activities at all.

Perry: [00:53:03] 100%. And it's that theme again, where wellness influencers start with biologic plausibility. And it's there. There is biologic plausibility here. And then they just jump to let me sell you this product without any of the steps in between. And when you look at those steps in between, you find that, uh, that stuff doesn't work. So maybe, I mean, should we talk about probiotics for a minute?

Emily: [00:53:31] Yeah. Let's talk about probiotics.

Perry: [00:53:33] All right.

Emily: [00:53:34] What do you think?

Perry: [00:53:35] I will give you three things that probiotics have been definitively established to be useful for. Um. Everyone ready? All right. By the way, multibillion dollar industry out there. So huge industry. Here are the three things preventing Clostridium difficile while you're taking antibiotics. Okay.

Emily: [00:53:59] Okay.

Perry: [00:54:00] Necrotizing [00:54:00] enterocolitis in premature infants and pouchitis which is an inflammation of the distal ileum in people who have had a colectomy. And that is it. The American Gastroenterological Association specifically advises against probiotics for inflammatory bowel disease, irritable bowel syndrome, or kids with gastroenteritis.

Emily: [00:54:24] It's disappointing.

Perry: [00:54:26] Which is what everyone is using this stuff for.

Emily: [00:54:28] Yeah, I mean, yes, those are all the things people. People use it for. Yeah. I mean, there are some reasons to think that this wouldn't work. Uh, so, you know, there's some reasonable evidence that the probiotic for most, for many people just never colonizes, like just gets sort of eaten by other bacteria. The other thing.

Perry: [00:54:50] Or.

Emily: [00:54:50] Digestive probiotics. Yeah. Digested. The other thing is these probiotics are just a bunch of different random stuff. And even if your problem was that you [00:55:00] were deficient in something that was causing some symptom, it's not at all clear that just taking the random probiotic that they sell at CVS or whatever was going to fix that particular set of issues.

Perry: [00:55:11] Right, right. It would be like someone saying, you know, you should take an antibiotic for that. And it's just like, oh, okay. There's a lot of different antibiotics. And then, of course, you know, saying that there are plenty of influencers and naturopaths and people who will tell you exactly which specific strain of whatever, and no doubt sell it to you as well. And I'll just say there's no robust data for any of them.

Emily: [00:55:38] You can actually pay people to test your stool and then sell you the stuff that will fix it. And what's so great is that when researchers have done this, they actually sent this one paper where they sent the same poop to a bunch of different companies, and they all, like a lot of them, just came back saying different random [00:56:00] things like, you know, they counted them differently. Wrong. Somebody said it was healthy. Somebody said it was it was unhealthy. You know, companies disagree with themselves. And then they're like, here's the supplement that you need to fix this problem. It's like.

Perry: [00:56:15] Um, it sounds like a great, a great business.

Emily: [00:56:18] Amazing business. $400 to test your poop. Plus you buy our supplements. It's I'm minting money. Where do I invest in this?

Perry: [00:56:27] Um, yeah, no, I mean, this is the direct to consumer world. Um, and it has all the trappings of science and it's just, it's, it's, this is a very complicated area. The testing is not easy. By the way, when you send poop in the mail, the bacteria isn't dead, right? Like it's going to continue to grow. So it'll change based on the temperature that it's sent at. You know, a lot of these are sent at room temperature. It'll change based on how long it takes to get to the facility. And when they're actually testing it and stuff, it's just there's no valid way to, to [00:57:00] do this for, uh, for health and clinical.

Emily: [00:57:03] Let me ask you a question. Do you think what share of these companies do you think are just getting the poop in the mail, throwing it in the trash, generating like a random set of data and then telling you to buy their supplements. You think it's like half? No, that no you don't. I don't I don't think you're so nice.

Perry: [00:57:19] Well, the testing is not like this is routine PCR testing. Like it's not expensive to do. It's it's hard to do.

Emily: [00:57:26] But it's just like you have to open up these boxes of people's poop that they shit. I don't know, man.

Perry: [00:57:30] That feels like outright fraud to me. I don't know, I like to believe in the inherent goodness of humankind.

Emily: [00:57:34] Wellness grifters. You like to believe in the inherent goodness of grifters. Okay, that's.

Perry: [00:57:40] The self-interested, self-interested ness. Um, I there's one microbiome study, and this is a little far afield, but I think it's such interesting science that I did want to bring it up. And that's the discordant twin obesity poop study. Can we talk about this? Yeah, yeah. But in, in [00:58:00] like, but in humans.

Emily: [00:58:01] Yes, yes. Yeah. Talk about this. This is I think.

Perry: [00:58:03] It's a cool study. Okay. So the, this is a study that prompted people to begin saying that obesity is a disease of the microbiome that we can fix the obesity crisis by somehow changing our microbiome. And it's a really fascinating study appearing in science in 2013. It's a very small study. Emily points out it's largely in mice, but hey, it's worth talking about because people mention it. So what they did is they took four female twin pairs who were discordant for obesity. So one of the twins had to have a BMI greater than 30 and the other couldn't. And they had to have at least 5.5 BMI points between them for at least several years. So they were really they were like different. By the way, only one of the four twin pairs were identical. The other, you know, the other three. It would be very hard to find identical twins that were this discordant on obesity, because so much of obesity is driven by genetics, so whatever. So three of the pairs were, you know, dizygotic [00:59:00] fraternal twins. Okay. But then what they did is they took germ free mice. So these are mice who have no bacteria. They're raised in a germ free environment. I think they're even birthed by C-section so as not to be colonized by their mom's vaginal flora.

Perry: [00:59:13] So germ free mice. And they gave them fecal microbiota transplant from each twin and let them eat like whatever they wanted. And the mice, given the obese twin feces gained more total and fat mass and developed like metabolic complications associated with obesity, like, um, you know, elevated blood sugar and things like that. Whereas the, the mouse that received the other twins just developed like a normal mouse. So sort of a compelling study to suggest that something is going on with the bacteria there. Um, are they releasing something that's encouraging, you know, more eating behavior? Are they slowing the metabolism by secreting some bacterial metabolite? We don't know. Interestingly, when they mixed the mice together [01:00:00] in the same cage, so the lean mice and the obese mice were put in the same cage. The obese mice lost weight, and the reason they lost weight is because they ate mice that eat each other's poop. That's like a mouse behavior. And so the obese mice ate the poop of the lean mice, and the lean mice ate the poop of the obese mice. But apparently, lean, lean microbiome dominates, and the obese mice lost weight. Now, I can't think of any reason that this isn't 100% applicable to human beings, can you?

Emily: [01:00:36] I can't think of anything, but it turns out the experiments, they're difficult to recruit for the experiments that ended poop eating. And so they haven't. For that reason, and many others, perhaps this is actually they've struggled to replicate this in, in humans. And so this hasn't, uh, not for the reason I said, but for other science reasons. So this hasn't kind of led to some microbiome related treatment for obesity.

Perry: [01:00:59] It hasn't. And there have been randomized [01:01:00] trials of probiotics for obesity. And they have really no effects. It doesn't seem like that's the driver in in humans.

Emily: [01:01:07] But it is very interesting. Yeah. All right. My big picture takeaway on the on the poop here is that actually you should be paying some attention to your poop if if for no other reason than like having a nice poop every day and not being constipated or having diarrhea really improves your life. Yeah, I think for most people, like that's just like that is a part like if every morning you just had one nice poop and you didn't worry about it for the rest of the day, like that's good. That's a good way to start your day. And there are some ways to make that more possible. But that is different from saying once you are at that, you're maxed. That's the poop, Max. There's no further poop maxing from there. I think that we need to be doing. That's at least my take.

Perry: [01:01:52] I think. You could not have said that better. Um, that's my hashtag poop goal. Um, and I think I'm, I think I'm pretty close. [01:02:00] I think I'm pretty close to being there, but maybe I need to eat more fiber like every other.

Emily: [01:02:04] No, you need to get a squatty potty. I don't understand. Just get a squatty potty.

Perry: [01:02:09] Okay. Squatty potty. Coming right up. All right, well, so I think I know where you're going to be on this, Emily, but smash or pass poop.

Emily: [01:02:17] Smash on poop, smash on poop.

Perry: [01:02:20] I agree. I'm thankful for for poop. And, uh, and more importantly, for, uh, regular poops on a Bristol stool scale of three to 3 to 4.

Emily: [01:02:33] Totally. All right, that's it for poop. Your mailbag. Question of the week. After the break.

Perry: [01:02:45] And now for our question of the week. By the way, if you have a question for Emily and I, reach out to us at wellness.fm. We would love to hear from you. All right, let's play it.

Mailbag: [01:02:55] Hi, Emily and Perry, this is Jamie from Boston. And my question is about all the water that [01:03:00] everyone is supposed to be drinking all the time. I feel like if I don't have my water bottle with me, I might die of thirst. Never mind my preschooler, who always has to have her water bottle at school. We didn't have this in the 90s when we were drinking from those unrefrigerated ceramic water fountains. Did water become more important? When did that happen? Why? Okay, thanks.

Emily: [01:03:25] Okay. Perry, you are a kidney doctor who grew up in the 1980s. So, uh, what is going on with the excessive hydration that's occurring now?

Perry: [01:03:34] You're not going to like what I say. Um. Drink more water is such an easy bit of wellness advice. Especially living in a country with robust access to healthy water supplies. Um, and with good water bottles. The truth is that most people get a totally adequate amount of water. So Physiologically, I [01:04:00] know, I know no one. No one's happy. Everyone's upset. Okay, listen, physiologically, thirst is one of the most powerful sensations that animals have. We become thirsty when the level of sodium in our blood, which is normally 140 milliequivalents per liter, rises to about 141 Milliequivalents per liter. So as the water is gone, the sodium gets more concentrated. 141 at that point, your brain is kicking in and you will find water. The only time that doesn't happen is if someone's incapacitated. And you know, we'll see people with high sodiums because no one's giving them access to water or if they have rabies and, you know, have hydrophobia. Your urine puts out water. It's mostly water, and it can dramatically vary the amount of water that it puts out. So you can put out about 20l a day of water in your urine if your kidneys are healthy. So if you're drinking ten liters of water, you know what? You're [01:05:00] just gonna pee that right back out and it doesn't do anything special. It doesn't help your kidneys, doesn't kind of clean them out. One exception is if you're prone to kidney stones, and having more dilute urine might reduce the risk of recurrent kidney stones. I have to say that. But like beyond drinking, when you're thirsty, there's not great evidence that drinking water that frequently improves your health. Sorry. That's okay. Those of you not watching this on YouTube or video platform, I wish you could see the faces that everyone. God, everyone hates nephrologists.

Emily: [01:05:34] I you're you're boring. And I feel that people are water maxing and you're trying to, you know, like, I mean, first of all, do you have an aula? Because my kids both have those. And that's a great water bottle. Oh, and you could be.

Perry: [01:05:49] I call it a wallah. I do my kids do have some.

Emily: [01:05:51] Yeah.

Perry: [01:05:52] My kids do. I, I even like give my kids water bottles to go to school every day. They all have their water bottles. They refill their water bottles. I just like [01:06:00] met like from a health standpoint, I'm like, as long as they're given access to water, they'll drink when they're thirsty. And that is all you need.

Emily: [01:06:07] Physiologically, I do find we've gotten to a point where like occasionally, if for some reason one of my children forgets their water bottle, like they sort of come home with this view of like, I almost died at school today. I didn't have my water bottle. All I could do was drink a small amount of water from the Rhode Island. We call it a bubbler, the water fountain. Okay, I only I had to buy water in a box and because otherwise I would have died. But I guess what you're saying is they wouldn't have died that quickly.

Perry: [01:06:36] Correct. I will say yes. The data is like, you know, on like skin turgor and stuff. You know, like there's, there's look, if it makes you feel good, that's great. That's totally fine. But I do think people maybe go a little bit overboard with it.

Emily: [01:06:52] You can drink too much water.

Perry: [01:06:54] Also, you can. It's it's hard.

Emily: [01:06:56] Mostly happens when you're running.

Perry: [01:06:58] Yeah yeah, yeah. Um, [01:07:00] water without electrolytes can cause hyponatremia where your sodium is too low. So like you dilute your sodium and you really need the sodium in your blood to keep your brain and heart working. And, um, the treatment of severe hyponatremia is very fun for nephrologists, but not very fun for the patients that we treat because that's, that's one of our diagnoses.

Emily: [01:07:22] All right, with that, that's it for us today. Stick with us next week when we will ask what's the deal with seed oils. Well this actually is produced in association with iHeartMedia. Our senior producer is Tamar Avishai. Our executive producer at iHeart is Jennifer Bassett. Our theme music is by Eric Deutsch, and our content is for educational purposes only.

Perry: [01:07:51] If you like the show, help other people find us. Leave a rating and review on Apple Podcasts or your podcatcher of choice and help us spread the word about the show. [01:08:00] You can follow us on Instagram at pod. And don't forget, we want to hear from you. Head over to wellness.fm and leave us a question for our mailbag or suggest a topic for a future show.

Emily: [01:08:12] We'll let the influencers have the last word.

Influencer: [01:08:15] Hey bestie. Here's a little squatty Potty hack to help you poop easier. So instead of keeping your knees wide, you're going to actually let your knees fall in. And that's going to create a little bit of hip internal rotation, which is going to open up the back side of the pelvis to give space for stool to exit our body. We're going to breathe it out. We're not going to strain and we're going to have a nice satisfying poop.