I am at work so I can't watch the video. I bet the answer goes something like that: Less jobs that involved sitting on your ass for 8 hours straight, more active for the rest of the day (e.g. you had to walk because less cars and public transportation) and of course real food and not junk crap.
Am I a genious or what?
Man, you've just Trumped all my previous expectations of human potential! ;)