We have really good family records dating back hundreds of years. What stands out to me is the number of my ancestors who regularly lived into their 80s or 90s 500 years ago. At the same time it's very easy to see that entire branches of the family were wiped out, probably by basic things like Flu, IE: when you see a bunch of young people in their teens or 20s die within a short timeframe, that's the most likely explanation. I'm just a layperson, but it certainly feels intuitive to say that physical work like they did (avoid cardiovascular disease), probably minimal non-processed food diet, and a whole lot of serious luck when it came to avoiding disease and especially childhood maladies, is probably what worked. Sure it's anecdata, but it seems very consistent across many generations.