not in their 20s but definitely not in their 80s like today. if you reached 50s you were a boss. a lot of things that we consider routine to fix today would have ended your life (broken leg/hand, infections, severe diarrhea, etc). We really under-appreciate how many things we have as tools to expand our lifespan today.

From what I remember, it was more like if you made it past adolescence, making it to 50 was about normal. All kind of beside the point; you seemingly rejected the relevance of the primitive human diet based on their life expectancy. I don't think that follows.

Considering that soldiers in Ancient Greece could only retire after 30 years of service, I think it's fair to say there were plenty of 80 year old "primitive" humans.

I think we're talking prehistory, pre-agriculture here.

that what i also though. at least 10000 years ago if not more