There's a distinct relationship between muscle mass, metabolism, and aging. Basically, the older we get, the more we lose muscle mass, and the loss of muscle means a slow-down of metabolism. The result is obesity, and numerous health risks abound. Those deleterious risks include high blood pressure, high bad cholesterol, low good cholesterol, type-2 diabetes, poor eye-sight, and higher risk of cancer, heart disease, or stroke. After the age of twenty most individuals lose basic metabolic rate of approximately three percent every ten years.