A plain baked potato is one of the better foods you can eat when you have diarrhea. It’s bland, easy to digest, starchy enough to help firm up loose stools, and rich in potassium, an electrolyte your body loses rapidly during bouts of diarrhea. Harvard Health includes boiled potatoes alongside the classic BRAT diet (bananas, rice, applesauce, toast) as a recommended option for stomach flu, food poisoning, and traveler’s diarrhea.
Why Potatoes Help With Diarrhea
Potatoes work on two fronts. First, they’re a starchy, low-fiber food when eaten without the skin, which makes them gentle on an irritated digestive tract. Your body breaks down potato starch quickly, especially when the potato is boiled or baked, so it doesn’t sit in your gut demanding heavy digestive effort.
Second, potatoes contain resistant starch, a type of starch that survives digestion in the small intestine and reaches the colon intact. There, gut bacteria ferment it into short-chain fatty acids, which stimulate your colon to absorb more sodium and water. Research from the National Agricultural Library found that resistant starch significantly reduced the duration of diarrhea in adults with cholera when used alongside standard rehydration therapy. A freshly baked russet potato contains roughly 3.1 grams of resistant starch per 100 grams, more than most other varieties.
Replacing Lost Electrolytes
Diarrhea drains electrolytes, particularly potassium and sodium. A medium baked potato delivers about 900 milligrams of potassium, which is roughly 20% of the daily recommended intake. That puts it in the same category as bananas and fruit juices, all of which MedlinePlus and BC Cancer specifically recommend eating during diarrhea recovery. Low potassium can cause muscle weakness, cramping, and fatigue, so replenishing it through food matters, especially if diarrhea lasts more than a day.
How to Prepare It
Keep it plain. The goal is a bland, low-fat food, so skip the butter, sour cream, cheese, and bacon bits. A small pinch of salt is fine and actually helpful since you’re losing sodium too. If you want any topping at all, a thin spread of plain, unsweetened yogurt adds mild probiotics without much fat.
Peel the potato or avoid eating the skin. Potato skins are about 52% fiber by dry weight, and most of that fiber is insoluble. Insoluble fiber speeds up transit through the gut, which is the opposite of what you want when stools are already loose. The flesh of the potato, by contrast, is mostly digestible starch with very little fiber.
Avoid anything fried. French fries and potato chips are high in fat, and fatty foods linger in the stomach and can worsen nausea and diarrhea. Harvard Health lists fried potato products specifically as foods to avoid during an upset stomach.
Boiled vs. Baked: Does It Matter?
Boiling a potato actually makes it slightly easier to digest than baking. Research published in the Journal of Functional Foods found that about 75% of the starch in a boiled white potato breaks down during early digestion, compared to roughly 50% in a baked one. That means boiled potatoes release their energy faster and require less digestive work. If your stomach is especially sensitive, boiling and mashing the potato (without milk or butter) may be the gentlest option.
That said, a plain baked potato is still well within the range of easily digested foods. The difference is modest enough that either preparation works. Choose whichever sounds more appealing when you’re not feeling well.
What About Cooled Potatoes?
Cooking a potato and then refrigerating it overnight roughly doubles its resistant starch content. A chilled russet potato contains about 4.3 grams of resistant starch per 100 grams, compared to 3.1 grams when freshly cooked. Reheating it preserves much of that extra resistant starch, particularly in red and yellow varieties.
This could be mildly beneficial for diarrhea since more resistant starch means more short-chain fatty acid production in the colon, which promotes water absorption. But resistant starch also acts as a prebiotic fiber, and increasing fiber intake too quickly can cause gas and bloating. If your gut is already in distress, a freshly baked potato eaten warm is the safer choice. Save the cook-and-chill approach for the recovery phase, when your stools are starting to normalize.
When Potatoes Might Not Be the Best Choice
If you have chronic kidney disease, check with your doctor before loading up on potassium-rich foods like potatoes. Damaged kidneys struggle to clear excess potassium from the blood, and high levels can cause dangerous heart rhythm problems.
For most people with acute diarrhea from a stomach bug or food poisoning, though, a plain baked or boiled potato is a solid choice. It’s easy on the stomach, replaces key electrolytes, and the starch itself helps your colon recover. Just keep it simple: no skin, no heavy toppings, and eat it alongside other bland foods and plenty of fluids.