Kittens need kitten food while they’re growing. Growing kittens need a food that can keep up with their metabolic demands and support an ideal rate of growth. This means more fat and protein are required, and their vitamin and mineral intake must be carefully balanced to avoid excesses and deficiencies (either of which can lead to growth and development issues).
They can transition to adult food once they’ve nearly reached their full adult size—which is usually around 10-12 months of age.