Time for Mush
Currently, the AAP advises parents to wait until their infants are six months old before giving them any food except formula or breastmilk. Complementary feedings do not increase total caloric intake or growth rate, and lack the protective components of human milk.
How much is enough?
During the first year, solid food is only a supplement — the baby's primary nutrition source remains breastmilk or formula. Don't panic if it doesn't seem like your baby is eating all that much.
Reasons for Waiting
By about six months most babies are physically ready to swallow solid foods. The tongue extrusion reflex, in which most things that go into a baby's mouth are quickly pushed out by her tongue, fades away. An older baby's digestive enzymes have matured to the point where she can fairly efficiently break down solid foods. Her intestines have started secreting a protein called immunoglobulin A (IgA), which prevents allergens from passing into the bloodstream. It's important to wait for these capacities to develop, because a breastfed baby may lose some of her protection against infections and allergies once she starts solids.
Be Patient
Besides the health reasons for holding off on solids, there are a few practical ones. Solids will quickly transform the reasonably tolerable smell of a breastfed baby's poop into foul sludge. Cleaning up spit-up stains will become challenging. If you've got a trip planned, take it before you enter the solid food stage; a couple of days' worth of baby food can really weigh down your suitcase. (You'll also be happier if you can postpone the challenge of feeding a baby squirming on your lap in an airplane seat.)
The only reason for jumping the gun on solids is if your baby is at least four months old and is acting like she's going to go ahead and start solids without you. Talk to your pediatrician before you do. She may be ready if she stares at you when you eat and grabs at your food, mouths all of her toys, can sit up (with support) fairly well, or nurses frequently or drinks huge amounts of formula but still seems hungry. Most importantly, she's ready if she doesn't immediately use her tongue to push out anything you put into her mouth.
But wait the six months — or a little longer — if you can. The window for the introduction of solid food is a lot wider than the window for the introduction of the bottle.
Try not to pass your food hang-ups on to your children. You many think tofu is gross and avocados are slimy, but your child may love them if you feed them to her without comment.
Babies can do without solids for as long as eight months without ill effect. Soon after eight months, however, your baby will begin to require the extra nutrients that come with solids. She ought to have a little experience with this new way of eating before that time comes, so starting daily eating practice sometime before eight or nine months is a good idea.
Your Baby Is Ready for Solids When …
She's at least four to six months old.
She's like a vulture when you're eating, ready to pounce on your food.
She stops sticking her tongue out when her mouth is touched.
She sits with support and controls her head well enough to lean forward when she wants more food.
She's almost ready to sit up on her own.
She indicates she's full when you are feeding her.
She drinks more than thirty-two ounces of formula, or breastfeeds six or seven times a day and wants more.
She's at least twice her birth weight or at least thirteen to fifteen pounds.

