The good doctor is right, but I would point out that as a Japanese man he likely didn't eat the American diet. So if I may: the four legs of the stool in no order are 1) purpose, 2) social network, 3) good food (as defined by age, activity etc, but mostly plants, and no junk food, no alcohol, no smoking etc) 4) move move move move move move move. I write on this regularly. Advice from a Japanese doc is fine, but we all have to filter it through his situation which is driven by the Japanese diet (heavy on the fish and veggies) and a lot more respect for the elderly. In America we are short on both of those. The best Rx for a good life is no Rx at all, but simple things most of us can do.