Remember that germs are microscopic, so even when a child’s hands don’t look dirty, they may be covered with bacteria. What to eat when you have the stomach flu. Bananas. Bananas contain little fiber but are high in potassium, an electrolyte that helps with mineral and fluid balance in the body. Applesauce. Applesauce offers nutrients with a mild flavor and easily tolerated texture. It also has a high water content to help replace fluids lost during illness.