Solid foods should not be used in place of milk as the primary source of nutrition. When newborns are 4 months old, they should still consume around 4-6 ounces every meal. According to the AAP, after infants reach the age of six months, they can consume up to eight ounces every four or five hours. However, most children will need less liquid and more solid food during the first year of life. The amount of milk a baby should drink depends on his or her age, weight, activity level, breast or formula feeder, whether or not he or she is taking vitamins, and other factors. The American Academy of Pediatrics (AAP) recommends that babies between the ages of 0 and 6 months drink at least 16 ounces of milk or milk product including cheese, yogurt, and other dairy products per day. This amount can be split into two or three smaller servings throughout the day. Babies who are 7 months old or older can start drinking water instead of milk if your doctor says it's okay to do so. But for babies under seven months, they should still be given milk or another lactose-free beverage such as soy or rice milk. If you're choosing between breast milk and formula, consider the amount of fluid your child is being exposed to daily. If you choose formula, be sure it has at least 1,000 milligrams of calcium per liter. Otherwise, your baby will suffer from osteoporosis later in life.