A Bland diet would be key for an upset stomach. bland is a diet of foods that are not irritating.
The soft/ bland diet consists of foods that are easily digestible, mildly seasoned and tender. Fried foods, highly seasoned foods and most raw or gas-forming fruits and vegetables are eliminated. Drinks containing Xanthine and alcohol should also be avoided
all milk and milk products, plain mild cheeses, cottage cheese, mild flavored vegetable juices, lettuce in small amounts, carrots, mushrooms, green peas, white or sweet potato, spinach
cooked or canned fruit without skins, seeds, or tough fibers, avocado and banana
white, refined wheat, seedless rye breads, plain white rolls, matzo, english muffin, bagel, pita bread, saltine, graham, or plain crackers
cooked, refined cereals like cream of whear, oatmeal, farina, cream of ice. Dry corn and rice cereals such as puffed rice or corn flakes.. just to name a few