When should we start? When your baby turns 1. Before that, she needs the specific nutrients that breast milk and formula provide, says Laura Jana, M.D., coauthor of the American Academy of Pediatrics's (AAP) book, Food Fights. Younger babies also may not tolerate the proteins in cow's milk well.
Whole or reduced fat? The AAP now advises that any child with a family history of obesity, cardiovascular disease, or diabetes drink 1% or 2% (but never skim) milk. Babies at risk of becoming overweight (both parents are overweight or the child is in the 85th or higher weight percentile) should also avoid whole milk, says Jatinder Bhatia, M.D., of the AAP's Committee on Nutrition.
How should I introduce it? "Most babies can go cold turkey," says Dr. Jana. If your tot balks, mix cow's milk with formula or breast milk in increasing amounts. (You can continue to heat bottles if your baby prefers.)