Muscles keep us healthy, strong and independent. It's where most of our calories are burned. So more muscle means we burn more calories, even at a resting state. In other words, muscles help us stay trim.
They also help us remain mobile as we age. It's a known fact that we lose muscle mass as we age, a condition called sarcopenia. Scientists aren't sure of the root cause, but do know that strength-training exercise along with how much — and what kind of — protein we eat, and how it is distributed throughout the day, may help minimize muscle loss.