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