Necessary hormones are released throughout the body during exercise, so an active person must consume enough fat to support this production. Estrogen seems to prevent harmful muscle-cell destruction because it is a potent antioxidant that shields cell membranes from damage during exercise. Like testosterone, estrogen also ensures that the bloodstream holds enough circulating growth hormone to promote cell repair and tissue growth. Estrogen also enhances muscle function via protein-synthesis, the body's breaking down of dietary proteins into amino acids, which are fundamental to creating new tissue cells. Estrogen also promotes the retention of calcium and phosphorus, two minerals that allow muscle fibers to contract.
Fats play other roles as well.
Sports nutritionist Nancy Clark, M.S., R.D., emphasizes that fat supplies specific essential fatty acids that compose cell membranes and regulate physiological functions, including cholesterol control. Your body needs cholesterol daily, and if you don't get it from an outside source, your system will manufacture its own. According to Maffetone, fat ensures hormonal regulation of not only immunity but also heart function and body weight. He adds that fat conditions hair and skin, supports internal organs and protects against radiation from light and x-rays. Fiona Bayly is a competitive runner, triathlete and freelance writer who lives in New York City.