Since infants stomachs are small, once the formula or breast milk they were fed is digested, they will need to be fed again. As a baby grows, he stays fuller longer between feedings and parents and caregivers can anticipate when a baby will need to eat again and thus develop a baby-driven feeding schedule.
Fortunately, babies let those around them know when they are hungry. Babies communicate when they are hungry by opening their mouths, trying to put their hands in their mouths, sticking out their tongues, moving their heads from side to side and displaying the rooting reflex – the head-turning and sucking movements that occur when you gently stroke the side of a healthy infant’s cheek or mouth.
As babies show signs of hunger, they also show signs that they are full. When a baby stops sucking or turns his head away from the bottle or breast, he may be indicating he is full.