Fried Foods. 1/10. They’re high in fat and can bring on diarrhea. Citrus Fruits. 2/10. Because they’re high in fiber and they are acidic, they can give some folks an upset stomach. Artificial Sugar. 3/10. Too Much Fiber. 4/10. Beans. 5/10. Cabbage and Its Cousins. 6/10. Fructose. 7/10. Spicy Foods. 8/10.