The Diary Of A CEO podcast recently interviewed gastroenterologist Dr Will Bulsiewicz. While their conversation may not be particularly appetizing – gastroenterologists spend a lot of time studying people’s poop – it contains numerous gems of wisdom relating to gastrointestinal and colorectal health.
Bulsiewicz goes into some depth when discussing the different colors poop can be, which colors are causes for alarm, and when you should see your doctor based on the appearance of your stool.
Looking at your poop is the easiest gut health self-check you can do
Casting an educated glance over your stool before flushing is “one of the ways that you can tell what’s going on” in terms of your gut health, says Dr Will Bulsiewicz. He’s an American board-certified gastroenterologist and author.
He says 60% of the weight of our stool is microbial in origin. As in, it consists of, or comes from, microbes, aka microorganisms. So if you want a window into your microbiome, Dr B says, “look at your poop”.
He goes on to discuss the UK’s Big Poo Review – the largest study into the nation’s bowel movements in history. It concluded in 2023, and found that the average poop rate for Brits is 1.7 per day. It also found that 1 in 5 Brits are constipated, while 1 in 6 have diarrhea.
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The ideal poop, Dr Bulsiewicz says, is like a “sausage, or a torpedo”. It’s longer than it is wide, holds its form, and is smooth rather than knobbly or bumpy. But what about color? What can the color of our stool tell us about our gut health?
Why you should keep a color chart next to your toilet
For most of us, most of the time, poop is brown. This is because of bile, Dr B says on the podcast.
The liver produces bile, which is involved heavily in the digestion of dietary fat. After a fatty meal, the gall bladder “squeezes”, or contracts, in order to transfer bile into the intestines. Here, it mixes with the food you’ve eaten, and absorbs dietary fat. This is what makes poop brown.
“Some people poop white,” he adds. If there’s a blockage that stops bile from mixing in intestines, then the unabsorbed fat produces a white hue in your stool. Similarly, if you’re struggling to process fat, such as if you suffer from chronic pancreatitis, you can have yellow poop. And it might leave an oil slick on the surface of the water in the bowl.
Green poop can be a sign of an ill gut. Giardia infection, for example, can turn poop greenish. Giardia is an intestinal infection. Its other symptoms include bloating and stomach cramps. But drinking lots of smoothies can also have this effect on your poop, so a greenish hue isn’t necessarily an alarm bell.
You can have bluish poop from eating lots of blueberries, so keep an eye out for that. Or from taking part in the Blue Poo Challenge.
Talk to a doctor if you see blood in your stool
“If you see blood in your stool, that’s not normal. That’s grounds to talk to a doctor.”
Red poop isn’t necessarily a cause for panic, but it can be. If you observe partial coverage, with bright red blood, this could be evidence of haemorrhoids, an anal fissure, or a polyp in the rectum. A fully red stool is more worryhing. The reason it’s so important to inform your doctor as soon as you see redness in your stool, however, is that it can also be evidence of colon cancer.
Colon cancer is highly preventable, but affects people in huge numbers. 150,000 people are diagnosed with it every year in the United States alone.
Dr Bulsiewicz says he has patients come into his clinic not knowing how worried they should be about small amounts of blood in their stool. He conducts a colonoscopy and, in some cases, finds a polyp. Sometimes he finds large polyps.
Polyps are a precursor to cancer. So, by removing the polyp, he and his team nip cancer in the bud. This is a lifesaving procedure, and achievable only because his patients were diligent in reporting their red stools to him early.
“The connections between the gut microbiome and colon cancer are as powerful as any type of cancer. What protects us? Fiber. And short chain fatty acids.”
A 5g increase in dietary fiber equals a significant reduction in risk of developing colorectal cancer, he says. So: eat your fiber, and check your stool!
Will Bulsiewicz, or Dr B online, is an American board-certified gastroenterologist. He received his MD from Georgetown University School of Medicine in 2006, and his MS in Clinical Investigation from Northwestern University in 2010. He’s a member of the American Medical Association, American College of Physicians, and the American Gastroenterological Association.
