Asteroids range in size from Ceres-the largest at about 950 kilometers (590 miles) in diameter and also identified as a dwarf planet-to bodies that are less than 1 kilometer (0.6 mile) across. The total mass of all the asteroids combined is less than that of Earth's Moon.
Only about one-third of the protein eaten around the world comes from animals raised for food. Much of the protein consumed around the world comes from vegetarian sources, including grains, legumes, nuts and seeds. Three grains -- wheat, maize and rice -- provide 60 percent of the world's energy, as well as a good percentage of the protein consumed.
Protein can be metabolized for energy when carbohydrate and fat are in short supply. According to Gordon Wardlaw and Anne Smith in their text Contemporary Nutrition, proteins comprise 17% of your body weight, which except for water, forms the majority of lean tissue. Dietary protein supplies your body with essential nitrogen, which is then used to reformulate needed body proteins.