I think he's referencing "Lifestyle diseases" or "Diseases of civilization", like diabetes and heart disease, which appear to be quite rare in tribal settings (

I think he's referencing "Lifestyle diseases" or "Diseases of civilization", like diabetes and heart disease, which appear to be quite rare in tribal settings (and not just because people die first of other things), but are commonplace in places like the modern USA. People are obviously living a lot longer, but it's hard to tease apart how much of that is (1) people not dying of communicable diseases, which used to be the #1 killer, (2) sheer quantity of food (i.e., not starving), (3) the decline of violence, (4) diet composition, and (5) a whole host of other things. We can't really just say "We're better now than we were then, so every change must have been a good change," without teasing apart correlation from causation. Otherwise in the 60s you could have said "People didn't used to eat lead paint chips, and now they do, and people are living a lot longer these days." http://en.wikipedia.org/wiki/Lifestyle_disease http://en.wikipedia.org/wiki/Lifestyle_disease