Generally, breastfed babies eat every two to three hours, and babies taking formula eat every three to four hours. For the first several months, babies shouldn’t go much longer than four hours without eating, since they don’t have enough stored sugar to “fast” longer than that. Little ones tend to show you they’re full by turning away, becoming distracted from feeding, or simply falling asleep. If the baby is still fussing or smacking her lips at the end of a bottle or breast, she’s probably still hungry. Babies getting enough to eat will generally have one wet diaper for each day of life up to a week of age, then will level off at six to seven wet diapers and (on average) three to four dirty diapers each day. The doctor will measure the baby’s weight at each check-up; appropriate weight gain (typically 20-30 grams per day for newborns) is another good indication that the baby is getting enough to eat.