Berkeley Wellness just released an alert titled "A Prehistoric Diet".
It reads in part:
"Few of our Paleolithic forebears had heart disease or cancer--but that was because they rarely lived long enough to develop such chronic disorders."
According to Wikipedia people in the Upper Paleolithic era had a life expectancy at age 15 of an additional 39 years meaning that lots of the 15-Year-Olds must have lived to an age at which many modern Americans get cancer and heart disease.
Assume we know that Paleolithics, including those who lived to an old age, almost never got cancer or heart disease. What might be happening for this to not indicate that the Paleolithics had some kind of protection from cancer and heart disease that we lack? Here's what I've thought of:
1) An equal percentage of modern people and Paleolithics have a natural immunity to cancer and heart disease. Paleolithics who didn't have this immunity were extremely likely (much, much more likely than those with the immunity) to die at a young age of something other than cancer or heart disease.
2) Before a Paleolithic got cancer or heart disease he almost always got precursor Condition X. Condition X almost never kills modern people (perhaps because modern people almost never get it) but almost always killed Paleolithics.