this could be from a multitude of things. most likely difficulty digesting some of the nutrients. It is hard to determine by healthy what times of foods you mean. increasing fiber with fruits and vegetables can cause bloating which your body should adjust to after increasing amounts. you can try gas-x or simethicone or bentyl to help with those pains. it may be a variant of gluten celiac disease or lactose intolerance if you notice it with those types of foods. consider gastroenterologist if persists