The first reason I don't drink skim milk is flavor - flavor is in the fat.
Second, butterfat helps the body digest the protein, and bones require saturated fats in particular to lay down calcium.
Third, the cream contains the vital fat-soluble vitamins A and D. Without vitamin D, less than 10 percent of dietary calcium is absorbed. In the American diet, whole milk was the traditional source of vitamins A and D and calcium. Skim milk - especially industrial skim milk - is an inferior source of both. Skim and 2 percent milk must by law, be fortified with synthetic vitamin A and synthetic vitamin D 3. There is evidence that both synthetic vitamins are toxic in excess.
Finally, whole milk contains glycosphingolipids, fats that protect against gastrointestinal infection. Children who drink skim ilk have more diarrhea at rates three to five times higher than children who drink whole milk.