Never will a person go through more changes in their diet than they do in their first year of life. An infant's diet starts out as complete liquid. It then moves into some solids with liquids. By the end of the first year, 50 percent of an infant's nutritional needs will come from complementary foods; the rest from breast milk or formula.
When your baby is first learning to eat solids, there is a standard schedule you should follow. At around four to six months of age, try incorporating a single grain cereal into your child's milk or formula diet. Once your baby has tried grain cereals and is ready to try something new, a variety of pureed foods can be gradually added (this includes protein foods, fruits, and vegetables).
By the time your baby is eight months of age, he or she will have probably mastered thicker purees and can chew and swallow food with more texture. By about 10 months of age, your child should be eating about ½ cup per day of both fruits and vegetables.