Getting good nutrition is vitally important to your health. It's true for babies, too!
Best nutrition for babies is breast milk. Babies should be breastfed for at least 6-12 months. If breastfeeding is stopped before 12 months, infant formula should be used until a year of age. Some mothers are not able to breastfeed for a variety of reasons, and in that case babies should be fed formula for the first 12 months.
After the first year, babies can drink whole milk, but not 2% or skim milk until age 2. Whole milk is a good source of essential fats that babies need for brain growth (but the fats are removed from skim milk). After age 2, the need for milk is much less, but milk and dairy can be used to supply protein and calcium that kids need. (Do not use chocolate or strawberry milk, as these are very high in fructose!)
We used to think natural juices were a healthy source of nutrition for babies, but with the obesity epidemic and the discovery of the toxic effects of fructose, the AAP (American Academy of Pediatrics) now recommends zero juice for both babies and older kids. Babies, older kids and adults should not ever drink juice. Even "100% natural, no-sugar-added" juice has more fructose than soft drinks like Coke or Mountain Dew. Eating fruit is good for kids, but not the juice. For example, orange juice concentrates the fructose of 6 oranges into a 4-oz bottle of "sugar water" and throws away all the good stuff (fiber).
What about vitamins? Breast milk and infant formula contain all the vitamins that babies need. The AAP also recommends using a multivitamin with at least 400 units of vitamin D, since most of our vitamin D comes from sunlight, and babies may not get enough of that. As a baby gets older, she should learn to eat a good variety of fruits and vegetables to supply most of her vitamins. Unfortunately, toddlers get picky, and most do not get the vitamins they need every day. I recommend starting a chewable vitamin by age 2 or 3.
After 4-6 months, babies can start learning to eat solids, starting with pureed foods. At first the taste will seem strange and baby may spit it out! Keep trying! Sometimes it takes 10 tries (on different days) to let baby get used to the new taste. Then he may end up liking it, tolerating it, or even loving it! Start with pureed meats (babies need protein the most), then go to vegetables. Don’t use the fruits in jars, as these have huge amounts of sugar. Real fruit is OK, because there is only a small amount of sugar with a large amount of fiber. But there is generally about 4 spoonfuls (18-20 grams) of sugar in an average small jar of baby food fruit.
The more variety the better, so mix it up. But try to avoid foods that are high in sugar. This includes sucrose, honey, brown sugar, natural sugar, cane sugar and high fructose corn syrup. All of these are high in fructose which leads to liver damage, artery damage, and diabetes. (see Health-byte on fructose)
Clip from USA Today, 2009: