My grandpa who lived in the city almost all his life ate tons of sweets, lots of meat, almost no vegetables, in his youth drank a lot and he reached 91. But he did walk a lot.
My other grandpa, who lived in the countryside most of his life and had a field and animals to take care of, reached 96. He had a great sense of humor. We still think what killed him was taking him to live in a city when he was 91, but who knows?
Medicine is not an exact science, like Math. Remember when bloodletting was standard practice?