Your body uses proteins mainly for building and maintaining all body tissues. During periods of growth infancy, childhood, adolescence, and pregnancy amino acids build new body, tissues. Throughout life new proteins form constantly to replace damaged or worn-out body cells.
Proteins in enzymes, hormones, and antibodies also help regulate many body processes. Enzymes are substances that control the rate of thousands of biochemical reactions in your body cells. Hormones regulate reactions. Antibodies help identify and destroy bacteria and viruses that cause disease in the body.
If you do not get enough calories from carbohydrates and fats, proteins from food provide the necessarv energy. However, proteins are a less efficient energy source than carbohydrates and fats. When proteins are used for energy, they are not available for building and repairing body tissue. Proteins should supply only 10 to 15 percent of the calories in your diet.