Introducing food to your baby too early increases the chances that he will develop allergies, obesety, and heart problems later in life. Many moms ignorantly feed their baby solids sooner because they think it will solve some problem with sleep or attitude.
It is generally recommended that you start feeding solids between 4 and 6 months old. There is no rush, so pay attention to whether baby is interested in the food you are eating. If you wait to late after 6 months, you may have trouble introducing new textures.
The American Academy of Pediatrics recommends you introduce foods in this order…
• Breast milk or formula
• Cereal (Rice, Oatmeal, and then Barley cereal)
• Fruit
• Strained vegetables
• Meat
Within 2-3 months of starting foods, baby should be eating a balanced diet including something from each food group in each day.
I personally started rice cereal at 4 months, and then did not introduce other foods until 6 months. With my first child, I started with pureed veggies, and by the time I got to fruits she refused them all. Now, at 6 years old, she still will not eat fruits, but absolutely loves veggies. With my second, I started with fruits. Now at 2 years old, he loved fruit, and eats only a select few veggies. If I had it to do over again, I would alternate fruits and veggies when introducing them instead of starting with just one food group.
http://www.aap.org/publiced/BR_Solids.htm