Human breast milk consists of mostly of water (88 percent), sugars (6.5 to 8 percent), lipids (3 to 5 percent), proteins (1 to 2 percent), amino acids, and salts. It also contains large quantities of lysozymes—enzymes with antibiotic properties. Human milk is bluish-white in color and sweet. The blue color comes from the protein and the white comes from the fat. There are approximately 750 calories per liter of breast milk.