You should usually follow the same general recommendation about food, with or without any disease: a balanced/low-fat diet (by decreasing or avoiding fast foods, fried foods), eat lots of fruits and vegetables, less starch, less sugary foods/drinks, drink more water/non-alcoholic beverages. The gallbladder is just a storage pouch for the bile manufactured in the liver (to aid in fat digestion/breakdown). The liver continues to perform its task well without the gallbladder.