For people with IBS constipation, vegetables, fruits, beans and whole grain breads, along with other high-fiber foods, are helpful, according to WebMD. For people with IBS diarrhea, foods with soluble fiber such as oats, whole wheat breads, fruit flesh (after peeling the skin off) and dried fruit are recommended.
Triggers for both IBS constipation and diarrhea vary by the individual, which makes maintaining a journal of foods that cause the disorder important. For people suffering from IBS constipation, refined cereals and breads, high protein foods, dairy products and diuretic beverages such as coffee worsen symptoms. Increasing fiber intake by a couple of grams each day until one reaches a daily target between 20 and 35 grams resolves the problem. Prune juice and dried plums are also recommended, as they are high in sorbitol. Hydrating with 64 ounces of water per day is also helpful, as stated by WebMD.
Foods with too much fiber can trigger IBS diarrhea. Other triggers include alcohol, caffeine, fructose and the artificial sweetener sorbitol. Eating large meals, particularly with fatty or fried foods, may also cause problems. For people with gluten intolerance, wheat-based foods may cause diarrhea as well. Keeping portions small, eating soluble fiber in moderate amounts to keep the colon from spasming, and avoiding foods at opposite ends of the temperature spectrum in the same meal are all wise strategies, reports WebMD.