The best source for information is studies done on the extremely old. The
best that I'm aware of is the two done at the U of Georgia Medical School
on people who live to be 100 (see Johnson in bibliography at website).

The first study was done of 100 year olds in the U.S, the second was
worldwide.  The second was done according to Prof. Johnson because
the first results were so unbelievable.  Both found high consumption of
saturated animal fats to be the only major difference between these
very old people and others.

BTW, lifespans increases in the developed world don't statisticaly
reflect medical and hygenic advances very well since lifespan began its'
rapid accent in the 1850s.  Diet during this time became more paleolithic
as first the railroads made red meat more accesable to the common man and
then the truck made fresh fruits and vegetables available year round.
Canning and refrigeration also helped in this transformation.

Of course Hominids have been hunting since the physiological adaptations
for hunting defined their type.  It may be safely assumed that any
creature who has a brain evolved to aim will throw rocks.  To have stone
tools, you must first throw rocks for a long time and observe how they
break. Even a human the size of a child can kill large animals by
throwing a rock at distances of at least 90 feet (thus the requirement
for batting helmets at little league baseball). Although sophisticated
spears have only been found as old as 400,000 years old, spear points
have been found in strata dated at twice that age.

But hunting with primitive weapons is a knowledge intensive activity.
Older hunters consistantly outperform younger ones even with todays
modern rifles and shotguns.  Thus there is an evolutionary advantage for
the entire band that those who consistantly bag the most prized fatty
animals would live the longest. Although there may have been fewer older
people in paleotimes, they lived as long as people do today and were
valued for their experience.

Ray Audette
Author "NeanderThin:A Caveman's Guide to Nutrition"
http://www.sofdesign.com/neander