Kittens can eat cat food when they are one and a half to three months old, but the cat food they are fed must be kitten cat food. In addition, when they first start eating cat food, they should use goat milk powder. / Soak the cat food in warm water until soft before feeding. However, it is best for kittens to consume breast milk before three months, because the nutrients in breast milk are more conducive to the growth of cats.