"For some reason the idea has grabbed us that the best weight throughout the life span is that of a 20-year-old."

"But there’s just overwhelming evidence now that as you go through life, it’s in your best interests to lay down some fat.... It is not my contention that the fatter the better.... It is my contention that the desirable range rises with age."

Said Dr. Reubin Andres — quoted in his NYT obit. He made it to age 89, himself.  Based on his research, he figured that we ought to lay in 6 new pounds per decade for the best shot at long life.