According to the Doctor:
According to Dr. William Evans of the U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, the single most critical step not only to retard, but also to reverse, the aging process, is strength-training exercise.
Dr. Evans states: "Much of what we call aging is nothing more than the accumulation of a lifetime of inactivity. Muscles shrink. Body fat increases. The results are an increased risk of diabetes, hypertension, and osteoporosis." He further explains: "It’s changes in muscle mass that trigger all the other changes. By preserving muscle mass we can prevent these problems from occurring."
It bears repeating, the single most critical step to stop and reverse the aging process is strength training.