I think it has more to do with sanitation than diet directly, many illnesses that kill that way (cholera, for one) flourish to this day in unclean areas, where

I think it has more to do with sanitation than diet directly, many illnesses that kill that way (cholera, for one) flourish to this day in unclean areas, where excrement contaminates the water/food. Not eating rotting food as well, which was normal for a very long time. Pretty certain that that accounts for a whole lot of diarhea and death. It does make me think of how little soil we are in contact with compared to paleolithic persons - I know that B12 is sourced from the soil in our alimentation, but since we wash our produce we don't get any, and if you don't eat meat you need to supplement. I wonder if there are not other bacterium that we are washing away. Also remember hearing that it could be picked up on your skin on contact, which is also not something most people do daily.