Philip J. Goscienski, M.D.
Conventional wisdom states that life expectancy prior to the Agricultural Revolution was about 18 years and that our distant ancestors rarely survived beyond the age of 30. The first figure is correct but the second is not. Life expectancy is an average, not a maximum. When infant mortality is high it drags down the average life expectancy. Lots of babies died back then for the same reason that they do now in undeveloped countries: no plumbing, vaccines or antibiotics. The presence of any one of those advances sends life expectancy soaring but it doesn't add as much to the length of adult life.
It's no surprise that lots of Stone Agers died of injuries early in life. A disabled hunter has a short future. We can never know how many of our distant ancestors ended up as some leopard's lunch, leaving not a morsel behind for future anthropologists to find.
It's certainly not true that Stone Age people rarely made it to what we would call old age. Anthropologists have known for decades that about 10 percent of humans lived beyond the age of 60 years during the Old Stone Age, the thousands of years that preceded the domestication of crops and animals. Modern-day hunter-gatherers that are untouched by the blessings of civilization also have a low life expectancy but about 20 percent of them do live past 60 years.
Stone-Agers were certainly not a fragile bunch. They were more muscular than all but the most highly trained athletes of the present day. Their skeletons reveal that they were taller than those people that lived after the start of the Agricultural Revolution. It wasn't until the middle of the last century that inhabitants along the shores of the Mediterranean became as tall as their pre-agricultural ancestors.
Humanity paid a price for the remarkable cultural achievements that followed the Agricultural Revolution. Every single group that discarded the hunter-gatherer way of life in favor of farming became smaller in stature, had a shorter lifespan and suffered from iron-deficiency, parasitic diseases, epidemics and high infant mortality.
History may be repeating itself. The 21st century is remarkable for its scientific advances, especially food production and the development of labor saving devices. We are also in the midst of the degradation of our health because of those very same advances. Increased lifespan (77.6 years in the United States) does not mean better health. Our healthspan, the period from birth to the onset of disabling chronic disease, has barely increased at all and it may be decreasing.
By mid-century the life expectancy of future generations will start heading downward unless we can slow down the twin epidemics of obesity and type 2 diabetes.
There are some signs that we're going to succeed eventually. I see more seniors at fitness centers. Food producers, anticipating government regulation, are finding substitutes for heart-damaging trans fats. School administrators are taking control of what suppliers place in on-campus vending machines. Milk is in; soda is out.
The health revolution has begun. Let's hope that we didn't start too late.
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at firstname.lastname@example.org.