本文来自微信公众号： 环球科学科研圈 ，作者：领研网，原文标题：《每天拉屎才算健康？关于排便，你可能信了不少误区｜科学60秒》
排便打卡时间到，今天你拉得还好吗？
随着各类“大X理论”（maxxing）接连涌现，从大睡理论、大水理论到大蛋理论，人们热衷于把生活的方方面面都做到“最大化”。
近期，英文互联网上兴起了一股“有味道”的风潮，被称作“大屎理论”（poop maxxing）：有人每天晒出“排便打卡”，有人分享晨起一杯温水的通便心得，还有人把粪便形状对照图存进收藏夹，时不时拿出来比对一番。
关于如厕习惯的种种讨论里，哪些值得借鉴，哪些又是毫无根据的“伪科学”？美国胃肠病学专科医师、患者胃肠健康科普平台“现代肠道”（Modern Gut）的创始人温迪·勒布雷特（Wendi LeBrett）对此很有经验。
温迪自2022年起在社交媒体上发布排便相关的科普内容。她发现，早在“大屎理论”流行之前，网络上热衷讨论排便的氛围就已经存在。人们对排便这个话题始终兴趣浓厚，乐于在网上分享各种改善排便的经验；温迪发布的排便小技巧也总能收获热烈反响。
人们在网络上谈论排便，远比在现实生活中坦然。不少网友会毫无顾忌地分享自己的排便情况；然而，医院胃肠科的诊室里又是另一番情景：即便面对的是一位以讨论排便为本职工作的胃肠科医生，一些患者仍会害羞、尴尬，连声说“这也太难为情了”。
互联网在某种程度上打破了这层隔阂，但在年龄较大或有特殊健康顾虑的人群中，这依然可能是个难以启齿的问题。
为什么坦然谈论排便如此关键？许多胃肠病学家都把粪便视作一项“生命体征”，它能直接反映身体内部的状况。近年来，50岁以下人群的结肠癌发病率持续上升，而排便规律的变化可能是身体出问题的第一个信号。
美国癌症协会（American Cancer Society）研究团队于2026年在《美国医学会杂志》（JAMA）发表分析，追溯了1990—2023年间美国50岁以下人群前五大癌症相关死因的癌症死亡率变化，发现结直肠癌死亡率自2005年以来每年增加1.1%，从癌症死因的第五位跃升至第一位。分性别看，它是同龄男性癌症死亡的首要原因，在女性中则仅次于乳腺癌，位居第二。
如果人们对这个话题避而不谈，选择默默忍受，就很难分辨正常和异常的信号。温迪接诊过一些一生都在与排便问题作斗争的患者，他们从未意识到自己的情况不对，原因很简单：从来没有人和他们聊过这件事。
随着排便话题在社交媒体上升温，“布里斯托大便分类法”（Bristol Stool Chart，也叫布里斯托粪便量表）也开始为更多网友所熟知。这一分类法由英国布里斯托皇家医院（Bristol Royal Infirmary）的研究者于1997年正式发表，最初用于粗略评估食物残渣通过肠道的时间：粪便越干硬，往往说明它在肠道中停留得越久。
它将粪便分为1型至7型，每一型配有对应的图片和文字描述。1型和2型是坚硬、呈颗粒或块状的粪便，这是便秘的表现；4型形似一根表面光滑的香肠，属于“黄金级”健康粪便；3型至5型都属于正常范围；6型和7型偏稀软，乃至呈水样，提示可能出现了腹泻。
这一量表的价值在于提供了一个通用的参照。“布里斯托大便分类法”可以帮助医患双方对“正常”有共同的判断标准：粪便应该是什么样子？所谓的“便秘”究竟指什么？即便它算不上完美的衡量工具，未能将粪便的颜色、排便频率、排便时的用力程度等指标涵盖在内，但作为参考和起点，已经够用。
每天排便，是肠道健康的必要条件吗？一些患者自述“便秘”，实际情况却并非如此，他们可能只是没有做到每天排便。温迪表示，这大概是关于排便最常见的一个误区。
不少人相信，排便次数越多越健康。但实际上，正常的排便频率范围相当宽松，从每天3次到每周3次都属于正常。有些人在便秘时反而更频繁地排便，因为他们会在一天里不断努力排出量少又排不干净的粪便。判断频率是否正常的关键在于找到属于自己的常态：如果你习惯隔天排便，感觉良好，没有任何不适，也从不为此烦恼，就不必过度担心。
关于排便频率与健康的关系，美国系统生物学研究所（Institute for Systems Biology）的团队2024年在《细胞报告-医学》（Cell Reports Medicine）上发表的一项研究提供了参考。研究者分析了1400余名健康成年人的肠道菌群、血液代谢物和生活方式数据，发现每天排便1~2次的人，其肠道中负责发酵膳食纤维的有益菌最丰富；排便过少的人，血液中与肾功能下降相关的蛋白质发酵副产物更多，排便过多的人则表现出更多与肝损伤相关的指标。
除了借助布里斯托大便分类法观察粪便形态，另一个重要指标是排便后的主观感受：你拉得是否顺畅、痛快？很多人都有类似的体会，一次通畅的排便之后，整个人都轻松了。相反，如果你每天都去厕所，却总觉得没排干净、有残留，伴随腹胀、频繁排气，或者常常突发便意，甚至来不及赶到厕所，这些都可能说明，你的排便状况还有改善空间。
健康的排便时间通常很短，从进厕所到出来大约……[查看全文]
Is‘poop maxxing’the key to health?
Rachel Feltman:For Scientific American’s Science Quickly,I’m Rachel Feltman.
Your social media feed is probably full of“maxxing”right now:“looksmaxxing,”“protein maxxing,”“sleep maxxing.”But what about“poop maxxing”?This year’s hottest trend might just be having regular bowel movements.
So what can we all learn from the current discourse on bathroom habits—and what advice should we try to tune out?Here to help us sort through it all is Wendi LeBrett.She’s a board-certified gastroenterologist and the founder of Modern Gut,a gastrointestinal education platform for patients.
Thanks so much for coming on to talk to us today.
Wendi LeBrett:Yeah,happy to be here.
Feltman:So we’re here to talk about,uh,one of many“maxxing”-related trends on the Internet right now,uh,“poop maxxing.”Do you remember,like,when you started coming across not just the phrase itself but this kind of vibe in talking about bowels on social media?
LeBrett:I definitely have heard of the vibe before hearing about the phrase itself,and maybe that’s,you know,partially my bias as a gastroenterologist who posts about poop on social media.
Feltman:Sure.
LeBrett:But since I’ve been posting on social media,since 2022,people have always been fascinated and interested about poop,and it’s funny,all the things people love to share on the Internet about poop and how to make your poop better.So anytime I share tips on how to poop better,I always get a warm reception.
Feltman:Yeah.Do you feel like people are more open to talking about poop on the Internet than they are in real life?
LeBrett:Absolutely.I think there’s a lot that people share on the Internet about their poop very freely,and I’m always really proud of them because I think it’s really important to talk about poop.Um,when I see patients in the office,you know,they’re seeing me,I’m a gastroenterologist.That’s literally my job to talk about their poop,and people are sometimes still embarrassed or shy,and they say things like,“Oh,like,this is so embarrassing,this is so awkward.”And I think the Internet kind of breaks down all those barriers.
Feltman:Yeah.Well,so let’s talk a little bit about why it is so important that people feel comfortable talking about this?
LeBrett:So I think a couple things.So firstly,your poop is—a lot of gastroenterologists say this—a vital sign.It tells you about what’s going on within your body.We are seeing rising rates of colon cancer in younger adults,so people under the age of 50,and your poop could be the first sign that something is wrong.And if we don’t talk about poop,a lot of people don’t realize what’s normal,what’s not normal,and people suffer in silence.I’ve seen patients who’ve had poop issues all their lives,and they didn’t know it was abnormal because nobody ever talked about it.
Feltman:Absolutely.And speaking of,you know,those indicators of health,one of the things that has,uh,become very popular on social media that apparently other people didn’t used to talk about all the time—it’s definitely been a big part of my conversational toolkit for ages—but the Bristol Stool Chart.Many people are encountering this for the first time.Could you tell us a little bit about what it is,what it’s good for and then maybe what its limitations are in terms of telling us about the health of our bowel movements?
LeBrett:Yeah,absolutely.So it’s a scale from one to seven.It’s really helpful because it has both pictures and descriptors about the different types of poop you could have.So types one and two,those are like those little hard,lumpy stools,that’s considered constipated.Four is what I like to refer to as the gold standard of poop,kind of like a smooth sausage shape.Between three and five is within the range of normal.Six and seven,it’s sort of mushier stool,diarrhea.And so it’s really helpful to have a guide because sometimes patients tell me,“I am constipated.”And it’s not that they’re constipated;it’s that they’re not pooping every day,and somebody told them,“You have to poop every day,”which is not true,and we’ll come back to that.But it gives them a guide to:What should your poop look like?What are we actually talking about when you mean you’re constipated?It’s just a,a reference so we’re all on the same page.
Feltman:Yeah.
LeBrett:So it’s not a perfect measure,and,you know,there are other markers of your stool that are not captured in the Bristol Stool Chart like color,frequency,how much you’re straining.So it’s not a perfect tool,but it’s,it’s a good reference and a good starting point.
Feltman:Yeah.So you mentioned the misconception that pooping every day is,uh,a prerequisite to having healthy bowels.Could you tell us more about what we actually know about frequency but also just,you know,other indicators of what healthy bowel movements are that maybe people have misconceptions about?
LeBrett:So I think there’s this belief that,oh,if you poop more times you’re healthier,or it’s better to poop more frequently.But what really is within the range for normal is anywhere from three times a day to three times a week,which translates roughly to every other day.And it really is,like:What is your normal?So if you’re someone who poops every other day,and you feel great,you don’t think about your bowel movements,you have no symptoms,you feel happy,I,like,reassure people,like,“That’s great.That’s your normal.You don’t need to worry about that.”
Some people actually find that when they’re constipated,they poop more frequently’cause they have these tiny little unsatisfying poops throughout the day’cause they’re trying to get things out.So it definitely is not“more is better.”So,I think appearance,so using the Bristol Stool Form Scale is an important marker of what is considered healthy,and then just like,how you feel about pooping.Like,do you feel like you had a good,satisfying poop?And I think many people can relate to that,that they feel better after having a good poop.Some people have the feeling that,you know,“I go every day,but I still feel like I didn’t poop adequately,”or there’s still something still left and they feel bloated,they feel gassy,they can’t get to the bathroom in time.So these are all things that are signaling to me,like,maybe your poop needs to be a little bit healthier.
And then the last thing I tell people,poop should come out easily.It should be...[full transcript]