One of the biggest criticisms people have of the way I eat (carnivorous paleo, i.e. caveman food) is that just because we evolved eating a particular way doesn’t mean those foods are necessarily the most optimal. Even if pre-agricultural populations lack the diseases (PDF) that will kill most readers of this blog, why would we want to emulate a life frequently thought of as “nasty, brutish, and short”?
The fact is, the average caveman lifespan is dramatically skewed by their high rates of infant mortality, bacterial diseases, and trauma. Without modern healthcare, a minor complication and birth or a simple ankle-twisting fall at age 50 could be fatal. This excellent paper (PDF) presents some key findings about caveman lifespans:
- Post-reproductive longevity is a robust feature of hunter-gatherers and of the life-
cycle of Homo sapiens. Survivorship to grandparental age is achieved by over two- thirds of people who reach sexual maturity, and can last an average of twenty years.
- The modal age of later adult deaths for hunter-gatherers is in the range of 65-75 years. In this age range we find mortality rates converging across populations. This is the closest functional equivalent of an “adaptive” human lifespan.
- Life expectancies for modern foraging, and presumably ancestral populations are typically low due to high infant and child mortality, but adult mortality rates remain low through the fifth decade of life.
- Illnesses account for 70%, violence and accidents 20%, and degenerative diseases 9% of all deaths. Illnesses largely include infectious and gastrointestinal disease, although less than half of all deaths in our sample are contact-related disease.
In short, once a caveman survived childhood, he had a pretty good chance of reaching ages comparable to ours, without the tens of thousands of dollars in medical care we use to compensate for our crappy diets. Could this be explained by lifestyle factors? To some degree, maybe: paleolithic man exercised more, sat less, and spent more time out in the sun. But even short-term clinical interventions with a paleolithic diet have shown rapid improvements in health and degenerative disease markers, so it’s likely that diet played a large role in ancestral health.