Life Expectancy of Hunter Gatherers (Paleolithic Humans)

I was first tipped to this by Chris at Conditioning Research, but thanks still go to Henry, a reader of Mark’s Daily Apple who recently provided a link to UC Santa Barbara anthropology professor Michael Gurven and University of New Mexico professor Hillard Kaplan’s three year old paper on life-expectancy in paleolithic humans.

The paper, entitled “Longevity Among Hunter Gatherers: A Cross-Cultural Examination” [Population and Development Review 33:2 (2007) 321-365; online PDF available here], is a gold mine for anyone interested in the question of paleolithic lifespan (not only in terms of data and analysis, but also bibliography).

In my experience, the average person on the street assumes that so-called cavemen typically lived to “about 30 years of age.” This widespread assumption leads many people to reject the “paleo-diet” or “caveman diet” for the simple reason that we have no reason to believe that paleolithic human beings lived longer or had a better quality of life than modern humans. This article provides a ready rejoinder to that point of view.

During the past several decades, many anthropologists have advanced a new view of paleolithic life expectancy. Kaplan and Gurven’s comprehensive study argues that the limits of human lifespan and the curve of average rates of mortality during different life stages may just be an evolved characteristic of our species, that has been present since paleolithic times if not longer.

A quote from the opening section of the paper:

Our conclusion is that there is a characteristic life span for our species, in which mortality decreases sharply from infancy through childhood, followed by a period in which mortality rates remain essentially constant to about age 40 years, after which mortality rises steadily in Gompertz fashion. The modal age of adult death is about seven decades, before which time humans remain vigorous producers, and after which senescence rapidly occurs and people die. We hypothesize that human bodies are designed to function well for about seven decades in the environment in which our species evolved. Mortality rates differ among populations and among periods, especially in risks of violent death. However, those differences are small in a comparative cross-species perspective, and the similarity in mortality profiles of traditional peoples living in varying environments is impressive.

In other words, the authors argue that, already by the end of the paleolithic era, humans had evolved into beings who can live productive lives well into their sixties, declining after their seventies. Modern humans have of course inherited this genetic, evolutionarily determined lifespan.

A mortality curve is a diagram of the changing rates of death for any given age group. The curve of human mortality, cross-culturally, is shaped like a saddle. Mortality rates typically start relatively high (defenseless infants are vulnerable to a variety of mortal threats), but decline rapidly in childhood. They continue to decline until early adolescence, then remain constant until middle age, and then begin to rise again, as the elderly succumb inevitably to entropy. In any population, ages of people run the gamut from infants to octogenarians and beyond.

Intuitively, the paper’s findings make sense. Our species spent several million years living as technologically advanced apes, in the mode of nomadic or semi-nomadic hunter-gatherer bands. During this period people did not typically “die at age 30.” In spite of the very real mortal threats faced by early humans — threats of death by accident, violence, disease, or catastrophe — the species evolved in a way that a human person can remain productive and vital into his or her sixties, and may easily live beyond that point, even though the decline into death is inevitable and the risk of death accelerates after age 70.

This was as true of “cavemen” as it is of modern humans.

Myth and Mortality

One thing that has changed, however, for modern humans is the mythic world-view adopted around the topic of death. Many ancient cultures had a mythic view of that accepted and explained inevitable death in light of some notion of cosmic order and purpose. But modern humanity seems to have embraced a radically different myth, one that is wrong, at least in its history. Our modern myth is a narrative of progress in lifespan. “Cavemen,” we say, lived lives that were nasty, brutish, and short quoting the philosopher, whereas modern humans will live ever longer lives. Death itself may be conquered by using a science of diet or medicine. So we tell ourselves. And we obsess with extending our span of life.

The article linked above may provide a useful corrective to the modern myth of the ever expanding length of human life, by helping to dispel the misconception that ancient humans lived pathetically brief lives in comparison with us lucky moderns.

Ironically, through the epic story of human origins told in Genesis, the Judeo-Christian tradition embraced precisely the opposite narrative: a story of decline in lifespan. According to Biblical epic, in the pristine beginnings of humanity, the first human and his spouse had access to the Tree of Life — a food that granted immortality. In theory they had endless lifespans. After being cursed by God and prevented from gaining access to that tree, the lifespans of the first couple turned out to be much longer than the average lifespans of their descendants, until, after a number of generations had passed, and the time of the flood had arrived, the maximum lifespan of human beings was finally reduced to the comparatively short period of one hundred and twenty years (Gen. 6:3).

The presence of this number 120 in the Biblical epic suggests that ancient peoples (the story is 3000+ years old) had a relatively accurate sense of the longest possible human lifespan. The figure 120 is quite realistic, as can be seen by looking at the list of the ten oldest verified people ever (see Wikipedia). Ancient peoples cannot have arrived at this notion of a “maximum lifespan” except through long experience with the phenomenon of human aging and its relationship to mortality.

In other words, the elderly were not unknown in ancient times, nor they missing from paleolithic human communities. Human beings have always grown old and died of “old age.” Only a modern conceit, one that accepts without criticism the inflated claims of the superiority of our “scientific” civilization, would deny this.

Recommended Additional Reading: “Paleo Life Expectancy” on Primal Wisdom.

Research Claims Paleolithic Man Ate Zone Diet

Kuipers et al, “Estimated macronutrient and fatty acid intakes from an East African Paleolithic diet” British Journal of Nutrition Online first printing Sep. 23rd, 2010.

The canonical “Zone” diet promoted by Barry Sears calls for 30% of calories from protein, 40% from carbohydrates, and 30% from fat. These Rx’d targets are subject to slight variation depending on individual needs, but according to Sears, the range of hormonally optimal ratios of protein/carbs run from 0.6 to 1.0, and higher levels of fat are acceptable for athletes and others whose energy expenditure is particularly high.

This paper, by researchers from the Netherlands, Britain, and America (the authors include Paleo-guru Loren Cordain) attempts to model a variety of hunter gatherer diets based on a database of available East African foodstuffs. The study argues that Paleolithic humans ate a diet that was composed of approximately 25-29% protein sources, 39-40% carbohydrates, and 30-39% fat.

Dudes, that’s the Zone.

If I were Barry Sears I would be jumping with joy today.

Beyond 30 days of “100% Paleo”

I’ve been eating an 80/20 (or even 90/10) “Primal” diet for a long time; well over a year, in fact. I began eating what I termed a “flexible-Paleo-Zone” diet in August, 2009. And I’ve read and studied “paleo” ideas of nutrition during all of that time, becoming something of a nutrition nerd. In the time since I started this process, I’ve given up alcohol for extended periods, and I’ve eaten more cleanly than just about anyone that I know, on average. But I’d never gone, you know, 100%. While others had “suffered” through giving up every prohibited paleo food, I had allowed myself flexibility and compromise.

Coming out of this summer, I felt that something was different. Something made me want to start fresh again this fall. I wanted to cleanse myself, and so I decided that maybe it was time for me to try a period of super-strict paleo dieting.

So, on August 22nd, I began my 30 day cleanse, a period of “100% paleo” nutrition. The plan was simple: kick start my semester, disrupt any bad patterns of eating I may have set for myself over the summer, and force myself to be a bit more creative with my cuisine. I hoped that the end result would be to reinforce all my best primal instincts with regard to nutrition. Mission accomplished. I got all of that, and more in the bargain.

The Details of My “100% Paleo” Diet

My diet, like the plan itself, was pretty simple.

Completely prohibited: sugar, alcohol, grains, legumes, dairy, and industrially “processed” or “packaged” foods, i.e. foods with lots of ingredients or industrially processed ingredients. No seed or bean oils or processed vegetable oils high in PUFAs, or foods fried in them.

Encouraged foods: anything whole, unpackaged, naturally produced, organic, local, minimally processed.

I did a lot of cooking; I carried my lunches; I didn’t eat out too many times. I chopped a lot of veggies. I would start my day with veggies, and ate veggies typically at every meal.

There was one not-really “paleo” structural restriction I imposed on my eating habits, which was that I restricted my feeding period to around 12 hours a day, between 8:00 am and 8:00 pm. This is basically a very moderate and mild form of “intermittent fasting.” Because I train in the morning, usually at 6:00 am, this meant that I was training in a fasted state.

My diet was a low-carb diet, meaning that fruit and starchy vegetables were somewhat restricted, or at least not preferred sources of calories. I would estimate that my daily carb intake ranged and varied from 50 to 150 grams a day; I really don’t think I did more carbohydrates than this at any time.

It was a very high protein and high fat diet, meaning that I allowed myself to eat protein sources (meat and eggs) virtually ad-libitum, and frequently indulged in high-fat foods like coconuts, avocado, and nuts during my eating window, if I felt hungry. I would estimate that I regularly ate over 200g of protein and 200g of fat per day. Altogether, probably I averaged between 2800 and 3200 calories per day.

It was a post-Zone diet, meaning that, at every meal I tended to always eat a combination (not to say a balance) of protein sources (i.e. meat and eggs), carb sources (green veggies, roots, fruits), and fats (nuts, naturally occurring and rendered animal fats, avocados, olive oil, and coconut oil). My post-Zone eating pattern is based on the tweaking of Zone eating first advocated by Robb Wolf, who pioneered the transition from Zone to Paleo-Zone cuisine when he was the official CrossFit nutrition guru. Robb essentially advocated a higher fat, lower carb version of the Zone, but he continued (and continues) to recommend a kind of balance of macronutrients be consumed at every meal.

The only supplement I used was fish oil (usually a tablespoon a day, yielding about 5.4g of Omega-3s). The main processed foods I allowed myself were unsweetened non-alkali cocoa powder, coconut butter, coconut oil, and olive oil.

For breakfasts I would eat 2-3 eggs, a bunch of bacon (always nitrate free) or occasionally some other meat, sometimes some smoked salmon. I usually ate greens with my breakfast, sometimes as my only carb, other times balanced with some squash or sweet potatoes, and small quantities of fruit. I would fry things in bacon grease.

I would drink coffee with breakfast and afterward, always black, but sometimes flavored with some unsweetened cocoa powder. My goal was to stop drinking coffee after noon. I didn’t always stick with that plan, but when I did, I was grateful for the better sleep that followed.

For Lunch, it was usually leftover dinner meats and dinner veggies. Maybe some nuts, usually some olive oil, occasionally some coconut oil. Sometimes a piece of fruit.

For dinner, lots of meat (wild, local, grass fed, free range and pastured pork, chicken, beef, bison, salmon, etc.) some more veggies, such as greens, cabbage, broccoli, squash, asparagus, etc., and plenty of olive oil or other source of fat.

After dinner, before 8:00 pm, additional protein or fats, like coconut butter, cacao nibs, almond butter, nuts. If I felt like having carbs, some small servings of fruit. Then, lots of water and tea.

The Aftermath

I maintained my weight over the course of the month, which was my goal. But I think, at least my scale suggests, that I lost 1.5 pounds of fat and gained 1.5 pounds of muscle. I’d like to think that I’m looking better. And except for my crappy performance in the Half Marathon, which I won’t blame on Paleo eating, I think I’ve had a good month in the gym. Bottom line is: I like how 30 days of “paleo” made me look and feel and perform. I look, and feel, and have performed at least marginally better than I was performing on my “flexible-Paleo-Zone” eating plan.

During past periods of privation, I’ve planned elaborate and gut busting cheating sessions. And as dedicated readers of this blog know, I love to describe these orgies of excess. But there was something weird about this go around. I never wanted to cheat. At all.

Yes, I miss my drinks on Friday and Saturday nights, and alcohol will be coming back into my diet, though in moderate moderation. But do I miss sugars, grains, or dairy? Not really. Not enough to want them back, even in small quantities or in “moderation.” So, I won’t be rushing back to add cream in my coffee, I won’t be adding daily indulgences of dark chocolate, I don’t want my morning oatmeal… and those were the three main indulgences that separated my primal eating habits from the 100% paleo crowd. I don’t feel the need for beans at all. Maybe I miss corn chips… but no, I think not really. I guess I could see having a big cheat on the right Mexican or Italian meal.

And the thirty days went so fast… one blow-out carnivalesque cheat day per month now seems excessive to me. I think it’s enough to allow myself to have a higher carb day a few times a month (i.e. extra potatoes and fruit), primarily as a cyclic “re-feed” for training purposes.

I’d like to explain all these things in more detail but it’s 9:30, 8 hours before I have to get up, so it’s time for bed.

Bottom line is: you’ll see me out this Friday, at Highland Brewing Company, drinking a few beers, but that’s the only food with gluten I’ll plan to consume for quite a while. So, yeah, I’ll drink some liquor now and then. And one of these days I’ll blow it out with a big mexican meal and a pint (or two) of ice cream or a piece of peanut butter pie or an entire cheesecake. For old times sake.

But as I move on into day 32 of 100% paleo (tomorrow), I’m not really looking forward or back to non-paleo eating. Strict paleo is the new normal. It’s the new foundation.

Don’t misunderstand me. I don’t actually plan to stay at 100% paleo. To paraphrase Robb Wolf, I’m not making paleo into a religion here. The alcohol tells you that. I do in fact plan to allow a few, selected neolithic and processed foods and supplements — and these are or may be dairy based (primarily, I’m talking about protein supplements). I’m going to try cross-breeding the “leangains” approach to diet and supplementation with a paleo foundation and see what happens. That’ll be a new 30 day period. Starting… in a couple of weeks.

Stay tuned. Cause I’m always trying new stuff out.

Sincerely, yours truly, the N=1 experimental subject.

“100% Paleo” (My Food Day in Pictures)

Here’s a look at my eating today. I ate three meals, at about 8:00 am, about 1:00 pm, and about 8:00 pm. Besides these foods, between and after meals I ate almost no snacks. Before breakfast I think I ate a few pieces of apple, and after work, I had a few more slices of orange, some apple, and ate some almonds. After dinner I ate a small plum. I started eating at about 7:45 am and quit eating at about 8:45 pm. I won’t eat tomorrow until about 9:00 am.

Breakfast: 3 eggs fried in bacon fat, over the top of fresh boiled dandelion greens dressed with bacon fat and apple cider vinegar; poached peach slices with cinnamon, a few slices of orange, some smoked salmon, and about 3 oz. of Hickory Nut Gap pastured pork sausage. And of course, coffee. I had unsweetened pure cocoa powder in my coffee this morning too, whipped into the hot coffee with a little battery powered whisk (the “Aerolatte”… a very useful kitchen tool—I finally agree with my wife on that one).

Lunch: a boatload of leftovers. Leftover wild Salmon (from dinner on Tuesday), leftover Rotisserie Chicken (from dinner on Wednesday), leftover dandelion greens (from breakfast), collard greens (from dinner Wed.), fig slices (also from Wed), boiled cubes of yellow beet and celery root (dinner Wed). It took just a few minutes, to throw this lunch together into my tupperware lunch plate and took it to school. Very yummy. I ate it cold, and loved it.

For dinner, I made a great salad with spinach, purple cabbage, chopped fig, chopped strawberry, toasted nuts, and dressed with a vinaigrette made of pureed strawberry, cider and balsamic vinegar, sesame oil, olive oil, and salt; I grilled some NY strip steaks from grass fed mountainside raised Hickory Nut Gap cows, and I grilled some zucchini after dressing them in olive oil, salt, pepper, and garam masala. And I sliced up an avocado. I shared this stuff with my wife and mother-in-law. I ended up eating maybe 12 oz. of steak (awesome), had about 3/4 of that avocado, the equivalent of a whole zucchini, and maybe 1/3 of the salad.

Yes this is a typical day and yes, I spend all my money on meat. At least that’s the way it seems sometimes. But… well. I don’t ever go out, lately don’t drink, and have few other vices. So, heck yeah I spend my money on meat. What else am I going to do? Invest in the stock market?

If you think some aspect of this diet “isn’t paleo” then… I guess you should let me know since I’m supposedly trying to be paleo during this 30 day window. But please be aware: I don’t give a shit about: too many eggs, arachidonic acid, saturated fat, fatty cuts of meat, salt, cured meats, vinegar, or “eating too much fruit” (which I definitely am NOT doing anyway, so, you don’t think that).