Do Bananas Cause Constipation — or Help You Poop?
When you're feeling backed up in the GI department, food can be your saving grace. A cup of coffee may have you making a mad dash to the bathroom in no time, and munching on a kiwi daily can help you drop more number twos throughout the week, according to research.
But when it comes to the effect of bananas on your poo, it gets a bit murky. Do bananas cause constipation or do they actually help you poop? Here, a breakdown of the latest research on the gastrointestinal effects of the little yellow fruit.
Do Bananas Make You Poop?
First, a primer on constipation: Constipation is defined as having three or fewer bowel movements per week, and the ones you do have may be hard, dry, lumpy, or difficult to pass, according to the National Institutes of Health (NIH). Most often, constipation can be treated at home, and the first step to doing so is simply incorporating more fiber-rich foods into your diet.
And bananas fit the bill. A medium banana is considered a good source of fiber, as it provides 3 grams of the nutrient (nearly 11 percent of the recommended daily intake), according to the United States Department of Agriculture (USDA). More specifically, bananas contain both soluble and insoluble fiber. Soluble fiber a type of fiber that dissolves in water to form a gel-like material, which helps to create a soft, easier-to-pass stool, Emily Haller, M.S., R.D.N., a registered dietitian nutritionist at the University of Michigan Health's Division of Gastroenterology and Hepatology, previously told Shape. Insoluble fiber, on the other hand, doesn't dissolve in water, and it helps promote the movement of material through your GI tract and increases stool bulk, which normalizes your BMs, according to the Mayo Clinic.
What's more, bananas also contain sorbitol, a naturally occurring sugar alcohol that can have laxative-like effects, says Nidhi Singh, M.D., a gastroenterologist at Northwestern Medicine. Sorbitol is poorly absorbed and pulls water into the gut, which can speed up your GI tract and increase stool water content. As a result, the sugar alcohol can help relieve constipation.
The resistant starch — a type of carbohydrate that "resists" digestion in the small intestine — found in bananas (especially when they're unripe or green) may also help move things along. In a 2014 animal study, constipated mice that were fed resistant starch extracted from bananas experienced faster movement of material in the small intestine and pooped sooner than the control group. While the results of animal studies don't necessarily apply to humans, resistant starch, in general, is known to help treat and prevent constipation, according to Johns Hopkins University. Plus, a separate 2018 study found that eating green bananas daily for eight weeks helped reduce straining and painful defecation among constipated children. (Related: What the Types of Poop You Pass Can Tell You About Your Digestive Health)
Do Bananas Cause Constipation?
Wait, if the yellow fruit can help you poop, can bananas actually cause constipation? Currently, there isn't much research investigating whether bananas cause constipation or not. But a 2005 survey found everyday people believe it can. In the survey of 1,000 people — including healthy controls, patients with chronic constipation, and patients with irritable bowel syndrome with constipation — bananas were the third most common food named by respondents as a cause of constipation.
It's also possible for bananas to contribute to constipation if you're eating too much fiber in general. Folks consuming 2,000-calorie diets should score at least 28 grams of fiber daily, and 90 percent of women and 97 percent of men in the U.S. don't meet the recommended intake, according to the USDA's 2020-2025 Dietary Guidelines for Americans. That said, if you're consuming more than 70 grams a day — whether it be by eating a boatload of bananas or following a strict vegan, yet varied, diet — you could experience negative side effects, including constipation, bloating, cramping, and, in rare cases, intestinal blockage, according to information published by Duke University.
On the flip side, unripe bananas could help alleviate diarrhea. One study found that consuming a rice-based diet containing cooked green bananas for seven days significantly reduced the amount of stool produced by children with persistent diarrhea. And another found that adding green bananas to regular diets shortened the recovery period for children with acute and prolonged diarrhea. "Because of the fiber content in bananas, the idea is it can help solidify your stool if you're already having diarrhea," explains Dr. Singh.
Based on the research available, bananas may be more likely to make you poop than cause constipation. That said, the exact GI effects of bananas will likely vary from person to person, says Dr. Singh. "It all depends on the individual," she says. "For some people, it won't bother them. For some, people it will." Regardless of how it impacts you, don't hesitate to reach out to a doctor if you think bananas — or any food, for that matter — are causing you to poop too little or too much. After all, only you know what's "normal" for your body. (Related: 12 Types of Foods That Cause Gas and How to Ease Their Effects)