Join Date: Oct 2006
Location: Louisville, KY
Frank, here is something I've written prior. Looking at the lifespan to determine optimal diet is impossible when there are so many factors.
Of course, a mention of a Paleolithic Diet brings up the argument that “our ancestors only lived to be 35 years old.” This argument assumes that early death was a result of subpar health. In dismantling this argument, we should first recognize that 35 years was the average life expectancy for our ancestors. If you recall from statistics class, an average is approximately the middle of a range of numbers, assuming that there are no extreme outliers (which in the case of age would be centenarians). So that alone means that we’re dealing with a range of approximately 0 to 70 years old.
The 20th century saw vast improvements in life expectancy which are most certainly not attributable to improvements in what we eat. If we look back just a little over a century ago to 1900, we see that average life expectancy at birth was only 47 years old.51 Looking around, it is obvious that we aren’t any healthier, yet we are living, on average, 50% longer. What gives?
The first answer to that dilemma is medical treatment, which enables people to survive things that would’ve killed them just a century ago, not to mention 50,000 years ago. For instance, today we can survive gunshots, knife wounds, falls from height, degenerative diseases, and broken bones due to medications and excellent surgical techniques. Parasites and infections that would’ve killed 200 or 2,000 or 20,000 years ago are now easily treated by doctors. A broken leg would’ve made a person a target to rival tribes as well as predators searching for dinner. Today, humans are not prey. The second answer is sanitation. It wasn’t too long ago that we lived amongst our waste, which is a breeding ground for the parasites and bacteria that we can so easily kill these days.
There is also a huge difference in the lifestyle led by hunter-gatherers and that led by modern Westernized humans. Basically, no one in modern culture has to worry about their dinner baring its claws and teeth and being turned into dinner themselves. Hunter-gatherers fought daily with animals that were bigger, stronger, and better equipped for killing than are humans with our lack of claws and fangs. Today, we go to the grocery store and pick up our steak or roast. Even modern hunters have little worry of being killed by their prey with their high-powered rifles and shotguns. Today, few people in modern societies have to worry about starvation, yet it was an ever-present reality amongst indigenous peoples.
We must also look at the infant mortality rate. While I don’t have data for 50,000 years ago, a few assumptions make it easy to see how medical improvements have vastly increased our average age by improving the number of people surviving to age 5 and beyond. In the year 2000, 99.3% of all babies reached age 1; in 1900, only 87.5% of babies reached age 1.52 In 2000, about 99.2% of all babies reached age 5; in 1900, that percentage was only 81.8%. Seeing the huge leaps in just 100 years, it isn’t out of the question to assume that (conservatively) at least 25% of all babies born in the Paleolithic era did not reach age 5. Given that, we have to assume that at least that many reached beyond age 35. In fact, looking at modern day hunter-gatherer tribes we see that many of them reach beyond age 60, well into old-age.
Finally, there is the argument that age 35 was simply too early to acquire the diseases such as cancer and heart disease. This also holds no water as Dr. Cordain points out in his article discussing our ancestral life expectancy.53 Dr. Cordain says it better than I ever could, so I offer this quote: “While chronic degenerative diseases generally produce mortality in later life, they begin much earlier, often in childhood. This allows comparison between age-matched younger members of industrial and technologically primitive societies. Biomarkers of developing abnormality such as obesity, rising blood
pressure, non-obstructive coronary atherosclerosis, and insulin resistance are common among the former, but rare in the latter. Measurements of muscular strength and aerobic power reveal similar discrepancies, again favoring individuals whose lives more closely resemble the ancestral pattern. About 20% of hunter-gatherers reach age 60 or beyond, but even in this age bracket, individuals from foraging and other technologically primitive cultures appear almost completely free from manifestations of most chronic degenerative diseases (osteoarthritis is an exception).” We can see that these diseases do not occur overnight; one is not cancer-free one day and cancerous the next.
http://www.cdc.gov/nchs/data/nvsr/nvsr54/nvsr54_14.pdf, Page 35
http://www.cdc.gov/nchs/data/nvsr/nvsr54/nvsr54_14.pdf, Page 26
Agriculture has won for one reason - quantity of calories. Natural selection works on "most" not necessarily "optimal". Agriculture, for all of its faults, has allowed the human race to proliferate beyond anyone's wildest imaginations. Agriculture is the only way of supporting 6 billion people. If fewer people starve to death, at a time when fewer people are dying from animal attacks due to improved security and villages, you will see a proliferation of people. But the archeological record shows vast decreases in human health at the same time. Agriculture has produced many humans at the cost of healthy humans.