If you're struggling with a bout of mild-to-moderate diarrhea, adding fiber to your diet might help. Look for foods high in soluble fiber, which absorbs water in the digestive tract. Mixed with water, soluble fiber turns into a gel, resulting in firmer, bulkier stool that moves more slowly through your system. If you have severe or persistent diarrhea, however, skip the self-medication and visit your doctor for a diagnosis.
Oatmeal, potatoes, bananas and soft, skinless fruits are rich in soluble fiber and may help with diarrhea. Sweet potatoes are an especially good soluble-fiber source, containing 2 grams per half-cup of flesh. For comparison, 1/2 cup of dry oatmeal contains 2 grams of soluble fiber, while the flesh of a medium baked potato contains 1 gram and a small banana contains just more than half a gram. The Dietary Guidelines for Americans 2010 recommends that you eat 14 grams of total fiber for every 1,000 calories, which works out to about 25 grams per day for women and 38 grams per day for men.