The grades of milk found at supermarkets are whole, 2 percent, 1 percent and skim, which refer to the amount of milk fat by volume. Whole milk is 3.5 to 4 percent milk fat, while skim milk is 0.5 percent fat or less.
A red bottle top signifies whole milk and one cup has 150 calories, 70 of which are from fat. Doctors recommend serving whole milk to children under two years of age because milk fat is rich in vitamin A, and saturated fats are necessary for infant brain development.
Milk with a blue bottle top is 2 percent, and a cup has 125 calories -- 41 from fat. It's ideal for those who'd like to cut down on saturated-fat intake without sacrificing taste.
A purple bottle cap denotes 1 percent milk, and a cup contains 102 calories, with just 21 from fat -- about half as many as 2 percent. Manufacturers often add vitamin A to 2 percent, 1 percent and skim varieties to replace vitamins removed with the fat. Protein-fortified reduced-fat milk is also common.
Sold in bottles with a light blue top, skim milk, also called nonfat milk, has had almost all fat removed. Each cup of skim milk has just 83 calories, with only two from fat. The thin flavor may take some getting used to, but skim milk delivers all the calcium, potassium and vitamins of whole milk without the saturated fat.