According to About.com, pet rats eat a variety of foods, such as block or pellet feed and a mixture of fruits and vegetables. Using a combination of commercial food and fresh food helps ensure that pet rats get the proper amount of nutrients.
According to DiscoverPetRats.com, commercial rat food that contains soy as the first ingredient is ideal. However, quality rat food should contain lower amounts of protein, because protein can cause skin issues. Rats enjoy eating a variety of fresh fruits and vegetables, such as apples, melons, strawberries, bananas, broccoli, peas, squash and carrots. Rats also enjoy eating whole wheat bread, pasta, cooked liver and yogurt.