I advise older people to shoot for BMIs in the 23+ range.
Dr. Reubin Andres, a gerontologist who advanced the study of diabetes but gained his widest attention for arguing controversially that weight gain in older people increases longevity, died on Sept. 23 at his home in Baltimore. He was 89.The issue is the energy needed to fight illness as one ages.
The body's tissues contain Calories.
Diseases are catabolic, i.e., they break tissue down.
The more tissue, i.e., Calories, an older person carries on his or her body (up to a point), the better able they are to sustain and survive the loss of tissue.
That is another reason why Anabolic Medicine tm is so important.