Whole Foods Specially for First Kittens (from 1 to 4 Months) at weaning. Baby cats grow so quickly that certain kitten foods aren’t tailored to their nutritional needs. A mother cat’s milk has protective antibodies to support her kitten’s natural defenses. But as a baby cat transitions to eating solids, their immune systems are still developing. This “immunity gap” leaves a kitten in a fragile state. With growing bones, emerging teeth, and developing immune and digestive systems, they need the right nutrition to grow strong.