Discussing one’s bowel movements is no longer the sole domain of toddlers, new parents, and seniors in fiber supplement ads. It’s become perfectly acceptable for your friends to offer up details about what certain foods do to their intestines while you’re seated at a table eating those very foods. Well, with that taboo out of the way, we might as well talk about it here, because it turns out that yes, your poop is important.

“Your intestinal health is critical because it nurtures the rest of your body,” Lea Ann Chen, says assistant professor of medicine at New York University and a member of the American Gastroenterological Association. In other words, bloating, diarrhea, constipation, or other forms of discomfort down there could also mean that the rest of your body isn’t absorbing the nutrients you need to function.

Just in case you’re wondering whether your poop is “normal,” next time you drop the kids off at the pool, compare them to this Bristol Stool Form Scale. It’s not the most precise measure of health, but it can be a good place to start. If you’re often staring at something on the higher or lower ends of that scale, or you feel bloated and gassy after certain meals, it’s time to reexamine the foods, drinks, and meds that might be messing with your plumbing.

For Everyone

Fried Foods

How sad is it that your mouth and your gastrointestinal tract will never agree about this category?

“We always worry about fried, fatty foods,” Chen says. “There’s not much good that can come from them besides that they’re tasty.”

Of course, we all know that delicious fried chicken, tempura, French fries, and the like can clog our arteries and put strain on our hearts, but the fats in those foods also do damage on their way to the bloodstream.

“I call fats the most high-maintenance macronutrient because they typically take a long time to digest,” says Dana White, R.D.

Studies have shown that diets high in saturated fats can increase constipation. While this study of rats indicated that the oils used in deep-frying foods can cause an imbalance in the gut microbiota, which in turn has consequences for how the intestines handle other foods, the research on humans is less conclusive. We do, however, know that saturated fat consumption can increase the prevalence of the bad gut bacteria that are associated with inflammatory bowel diseases.

Sugar Alcohols

Though the name may conjure up delightful images of strawberry daiquiris, the term “sugar alcohols” actually refers to a group of chemicals (xylitol, mannitol, sorbitol, and others) that occur naturally in some fruits and vegetables but are also manufactured for use in processed low-calorie foods. They don’t contain many calories because your body can’t fully digest them.

“If you can’t digest something efficiently, it sits in your gut and ferments, and that causes gas, bloating, discomfort, and potentially diarrhea,” White says. Don’t confuse this issue of foods fermenting in the gut with the foods that are already fermented before you eat them (and are good for the gut microbiota), White explains.

Alcoholic Drinks

White is no fan of the empty calories that come with alcoholic drinks and their sugary mixers. Sometimes, a night of drinking can cause diarrhea because ethanol has been found to accelerate digestion. But alcohol’s diuretic effect can also lead to dehydration, which in turn can cause constipation. Either way, drinking in excess isn’t great for you—as you’ve probably heard before.

For Some People


“The normal thing that happens is people lose their ability to digest a lot of dairy, and the ‘mutant,’ if you will, is the person who can continue to digest those foods into later adulthood,” Chen says.

But that does not mean that everyone should avoid all dairy, all the time. Not everyone is intolerant, and not all intolerances look alike, White says. Some people can eat cheese but not drink milk, while others can have those, but ice cream is off the menu.

“It’s not as black or white as people want to make it out to be,” White says. So even if you notice some dairy products make you feel gross, you may still be able to have fermented versions, like kefir or Greek yogurt, which are beneficial to your digestive health.


The recent trend of self-diagnosing a gluten intolerance without seeing a medical professional is worrisome, White says. Someone experiencing GI discomfort might see improvements by eliminating certain gluten-containing foods from their diet, but they may misinterpret their results.

“If you’re eating a lot of breaded, fried foods, and you cut those out because of the breading, and then you feel better, you can’t be certain what to attribute that to,” she says, explaining that either the gluten or the high fats could be the culprit in that scenario.

On the other hand, someone may begin to feel better by eliminating some major sources of gluten, such as bagels and pizza, and then stop there. But that’s not going to cut it for someone with celiac disease—as opposed to a milder gluten intolerance.

“You don’t really know it’s celiac without doing the proper diagnostic procedures,” White says. “If they’re still consuming malt and barley, soy sauce, or beer—things that also have gluten in them but are more inconspicuous—they could still be doing major damage to their digestive system.”

High Fiber Foods and FODMAPs

This is one of those “damned if you do, damned if you don’t” situations. When you eat too many starchy, refined carbohydrates, that usually means you’re not eating the high-fiber foods your body needs to create a healthy gut microbiome.

The good bacteria that create your microbiome consume fiber, producing some of the nutrients, such as amino acids, that our bodies need. And yet, high-fiber foods sometimes also cause problems.

“Sometimes I have patients who are eating a lot of vegetables—things like celery and broccoli—and these tough-to-digest foods also cause gas and bloating,” Chen says.

Some of those people may be suffering from irritable bowel syndrome (IBS), a frustratingly vague illness that has no known cause or cure as yet. Nutritional scientists have developed a list of foods called high FODMAPs (fermentable oligosaccharide, disaccharide, monosaccharide, and polyols) to avoid, and there’s evidence that it works to reduce symptoms.

“I’ve seen a lot of people be successful going on a low FODMAP diet, where they’re eliminating particular substances that do tend to stick around and ferment in the gut, causing those horrible gas-bloating-diarrhea symptoms,” White says.

That’s great news for anyone with IBS, but neither White nor Chen thinks you should just go on a low-FODMAP diet unnecessarily because the long list foods you have to skip includes a lot of stuff that’s otherwise good for you.

Can’t we just get a fecal transplant and go back to eating everything?

Chen says she gets a lot of calls from people who’ve read up on the gut microbiome and want one of these poop transplants for themselves. While this procedure has been shown to help patients with severe c.diff infections (that’s a bacterial infection in the intestines), the science isn’t quite there for other indications.

“The microbiome can be such a powerful thing, but we really don’t know how to use it,” she says.

And while we’d love to be able to cancel out any bad food decisions with a serving of kimchi, it’s not quite that simple, White says. A better idea might be to ensure you eat healthily on the regular.

“That would put you in a better position, so when you eat something that’s not so great for your gut health, the consequences would be less severe,” she says. “Maybe you can be more proactive than reactionary.”

Another good option: Work with a physician to get tested for gut health—which can help you determine which foods you want to especially avoid. There’s no one-size-fits-all plan, after all!

Sabrina Rojas Weiss lives in Brooklyn, surrounded by her fellow freelance writers and competitive stroller-pushers. Follow her on Twitter @shalapitcher.