What should children eat if they have diarrhea? Dietary fiber foods When children have diarrhea, parents can give their children more dietary fiber foods, such as fruits such as apples, bananas, pears, and pineapples, whole grains such as oats, whole-wheat bread, and legumes. These foods contain high dietary fiber, which can increase intestinal peristalsis and absorb water in the stool, thus detoxifying