
The American Academy of Pediatrics says, "babies don't need other foods in their diet until somewhere in the middle of the first year of life." This statement is very useful, because it doesn't say your baby needs other food at some specific age. You can let your baby be your guide. And babies will tell you when they are ready for solids, somewhere between 6 and 12 months. Like breastfeeding: "watch the baby, not the clock." Prior to that time, an infant's digestive system is not mature enough to digest foods other than human milk adequately.
You may notice that your baby may think he/she is ready for solids, may be grabbing food off your plate, and enjoying the new taste. But later in the day, the baby may have an upset tummy, become constipated, or you may see the food come out in the diaper, in the same form as when it went in, completely undigested. Your milk remains the perfect nutritious food for your baby, until his system is ready for table foods.
If you've started solids, you can stop, and try again a few weeks later. Also keep in mind that four months is the bare minimum age at which your baby might be ready for a taste of solid food. It's much more common for a baby to be ready for solids later in his first year. If you are a first time mother, you may be eager to try it.
When your baby does start solids, remember to breastfeed first and then offer solids. Your baby doesn't need big quantities, a teaspoon or so. Other foods still aren't as good as breast milk during the first year; you're just trying to get baby used to other tastes and textures. Mashed banana is an easy food to start with; babies almost always like it. Protein foods come early in the rotation, mashed pieces of meat. Eggs should wait a little while.
When you start feeding your baby solids, introduce only one new food at a time, and wait a week before trying each new food. This way you can watch for any signs of allergic reaction (such as rashes, hives, wheezing or diarrhoea). If you have a family history of allergies, you need to be especially cautious. Foods that are commonly allergenic include cow's milk, eggs (especially the whites), citrus fruits, peanuts, wheat, and corn.