I was just randomly googling the main paleodiet site and found this article which debunks the notion that palaeolithic humans lived very  short lives:-

http://paleodiet.com/life-expectancy.htm

I have to admit that up till now I had sort of assumed that palaeo humans could not have lived much into old age except possibly  for  tribal shamans  who might have been well-protected by their tribes. But the various arguments in the article  are very persuasive.

Geoff