If a baby is gaining weight at a normal rate he is getting enough food. If a baby sleeps three to four hours between feedings he is getting enough. An average baby takes 2-3 oz. per feeding between one and two weeks of age, and about six to eight ounces by the end of the third month. Overfeeding may cause symptoms of vomiting, colic, gas and diarrhea. It may also create a habit of over eating which may persist into adult life and lead to obesity.