Lack of exercise is one of the most important causes of accelerated bone loss and loss of muscle in the normal process of aging.
Exercise builds and strengthens bone and muscle and therefore is a bone and muscle preservative.
Muscle burns more calories than fat, so the more lean muscle you have, the more calories you will burn. With dieting alone, muscle is lost as well as fat. Along with a balance low fat diet, the way to lose fat and not lose muscle is through exercise. Aerobic exercise is unparalleled for burning stored fat and building lean muscle. Aerobic exercise should be regular and consistent.