According to the Royal Society for the Prevention of Cruelty to Animals, a hamster should never be given rhubarb or grapes as these can be poisonous to rodents. Other foods to avoid giving to a hamster include citrus fruits, the leafy parts of a tomato, fatty meats, beans, potatoes and almonds.
A hamster should be given a healthy balanced diet including a commercial pellet ration that features a variety of seeds. Hamster owners should supplement commercial food with a small quantity of greens, clean root vegetables, apples and other fresh fruit a couple of times a week. These small pets should also have access to fresh, clean drinking water at all times.