Although healthy infants can vary considerably from one another in their caloric intake, appetite is likely to be the most efficient way to determine what an infant needs. Most infants instinctively know how much food they need and will not undereat or overeat unless pressured. Babies should be fed when hungry but should not be forced to finish the last few ounces of formula or food. The baby's physician can check whether growth and development are progressing normally. Babies need fat.
Nutritional requirements are higher during infancy than during any other period.
At the same time, stomach capacity is limited, so food sources must provide sufficient calories and nutrients in a small volume. Infants require fat in their diet for normal growth and development. Infants and young children who eat a highly varied diet will consume enough fiber for their needs. A diet high in fiber may be too low in calories and may interfere with absorption of iron, calcium, magnesium, and zinc. Babies need sugars in moderation.