That doesn't prove a "varied diet" is the healthiest, though, for most people. Perhaps he would have lived even longer if he had eaten differently. If a person smoked like a chimney and lived to 93 that wouldn't prove that smoking is healthy. You have to look at a population. As I said, I think the standard western diet increases your chances of getting one or more of the "western diseases", but doesn't guarantee it, just like smoking increases your chances of getting lung cancer, but doesn't guarantee it.