Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
3 Nov

Just How Long Did Grok Live, Really? – Part 2

Speculation on ancestral lifespan is fun and potentially illuminating, but I think examining living, albeit imperfect, examples of modern hunter-gatherers offers greater insight. Sure, the environment has changed, wild food sources have shrunk in diversity and availability, and modern civilization has encroached and meddled and disrupted, but the few remaining hunter-gatherer populations exhibiting relatively untouched traditional lifestyles represent the most promising window into what life actually looked like and how long it lasted for our ancestors. Luckily, a couple of researchers – Gurven and Kaplan – had the bright idea to look at ethnographic studies on actual, living HG populations and analyze the available data on actual lifespan and mortality therein. They found some interesting stuff.

This study (PDF) has been floating around for a while. Readers have sent it to me on several occasions, and I believe it’s been mentioned in other bits of the online ether (blog comments, etc). The earliest I saw it was over a year ago on Ryan Koch’s blog.

The populations they looked at were given classifications: hunter-gatherers; forager-horticulturalists; and acculturated hunter-gatherers. Hunter-gatherers were groups without significant contact with outside cultures and included the !Kung, the Ache, the Agta, the Hadza, and the Hiwi. Forager-horticulturalists hunted, gathered, and used some agriculture. They included the Yanomamo, the Yanomamo Xilixana, the Tsimane, the Machiguenga, and the Gainj. Acculturated hunter-gatherers/foragers had significant, steady contact with outside cultures and included Northern Territory Australian Aborigines, the Tiwi, and the Warao, as well as other !Kung, Agta, Hiwi, and Ache groups. Gurven and Kaplan also looked at Swedes from the mid 18th century.

On average, 57%, 64%, and 67% of children make it to 15 years among “untouched” hunter-gatherers, forager-horticulturalists, and acculturated hunter-gatherers, respectively. That makes perfect sense, given what we know about child mortality rates in HG populations. The “wildest” groups, the HGs, who rely on hunted and gathered food also experience the most childhood deaths, while the hunter-gatherers with similar diets but presumable access to certain modern trappings enjoy the best childhood survival. It’s important to note that the acculturated groups in this study were characterized by increased access to immunization and medical care, especially for children; acculturation of traditional peoples hasn’t always had such a beneficial effect on their health and longevity (consider the health of Native Americans relegated to reservations, white flour, sugar, and vegetable oil). In fact, first contact with industrial or “civilized” cultures usually resulted in a massive initial increase in childhood mortality (diseases, mainly; the Ache lost about 40% of their population to foreign disease), but post-contact was characterized by lower childhood mortality, even compared to pre-contact rates. Mortality reductions in contacted hunter-gatherers were greatest in childhood and declined as populations aged.

Of folks who hit age 15, the percentage of hunter-gatherers who make it to age 45 is higher than the percentage of forager-horticulturalists who make it to age 45, but not by much – 64% to 61%. Acculturated hunter-gatherers excel here; 79% of their 15 year-olds make it to age 45. You might even say the study’s acculturated hunter-gatherers were essentially Primal, eating and moving traditionally while enjoying access to modern medicine.

From age 45, the mean number of expected remaining years of life is 20.7, 19.8, and 24.6 for hunter-gatherers, forager-horticulturalists, and acculturated hunter-gatherers, respectively. Give or take a few years, they could all “expect” to live about two decades if they were still alive by age 45 – a far cry from a “nasty, short, and brutish” existence.

There was variability among different populations within each category, of course, and at a later date it might be worth it to examine the differences in lifespan and lifestyle (diet, illness, etc.) among, say, the Ache and the !Kung to see if they align with our Primal perspective. The Ache, for example, rely heavily on hunting, traditionally obtain upwards of 80% of their calories from animals, and have high levels of homicide (including infanticide and warfare with rural Paraguayans), and they tended toward greater adult mortality.

The authors have no allegiance to or interest in the Primal Blueprint diet, but we can glean a few things that relate directly to our interests. First, it demolishes the common refrain that hunter-gatherers all die young. Average life expectancy is marred by infant mortality rates, and it’s clear that hunter-gatherers – the closest analogues to our Paleolithic ancestors – can and do enjoy “modern” lifespans with an average modal age of 72 years.

Second, Gurven and Kaplan show that “degenerative deaths are relatively few, confined largely to problems early in infancy.” Heart attacks and stroke “appear rare,” and the bulk of deaths occur when the person is sleeping and are free of obvious symptoms or pathology. Most “degenerative” deaths are attributed to “old age.” “Illness” is the main cause of death among all age groups and all populations, except for the pre-contact Ache (supreme hunters), and the authors break illness into different categories. The big killers were infectious respiratory diseases, things like pneumonia, bronchitis, and tuberculosis. Gastrointestinal illnesses also did a number on them, accounting for 5-18% of deaths, with diarrhea (probably stemming from parasites and coupled with malnutrition) taking the lion’s share. Violence was also a significant killer.

Third, and this is crucial, it destroys the other common argument that an evolutionary diet high in animal products might still be harmful because we didn’t evolve to live past forty, which is when diet-related diseases begin to show. Gurven and Kaplan make an extremely salient point: since the bulk of human evolutionary history took place over the course of 2 million years prior to the advent of agriculture, and that pre-agricultural period conferred most of the “major distinctive features of our species, such as large brains, long lives, marriage and male investment in offspring,” it’s likely that the “age-specific mortality pattern” of human beings also evolved “during our hunter-gatherer past.” That is, they propose that the human potential for longevity is not a product of modern living; instead, it appears to be a genetic characteristic shared by all Homo sapiens. Advances in medical technology bolster and support that inherent longevity (as shown by moderate lifespan increases in acculturated hunter-gatherers and modern industrial populations), but they aren’t responsible for it.

This data shows that human longevity is not a product of modern living. It shows that we have inherent proclivities toward long life, as long as we satisfy certain criteria – namely, the steady acquisition of food and shelter and the avoidance of infection, trauma, illness, and violent injury. The evolutionary lifestyle that eschews modern industrial processed food and promotes healthy levels of activity is the same one that supported our evolution into long-living Homo sapiens. Modern technology, sanitation, and medical advances are merely the cherries on top of an already solid framework.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Humans probably have an genetic max life span of one hundred years. A diet rich in carbs probably have implications in the development of diabetes or heart disease for certain persons (like me, of course) but you are not going to live 120 years only being primal! You have an age limit but you don´t know where is…Until you are there 😉

    El Grok wrote on June 1st, 2011
  2. Hi Mark, is there an article like this in a journal with a higher journal impact factor? I’m trying to convince a researcher, and with an impact factor of only 1.588, she’ll just dismiss this regardless of what it says. Thanks.

    Sadie Palmisano wrote on July 5th, 2011
  3. Excellent post! very interesting study and analysis.

    Carl@ hip exercises wrote on July 7th, 2011
  4. Great analysis of life longevity and how modern advances have increased it.

    I wonder though, how much greater todays average lifespan would be in the US, if it stopped producing twice as much food each day as the population actually requires!

    DANNY wrote on September 17th, 2011
  5. My family are mostly Seventh Day Adventist. We are all extremely long lived by U.S. standards. Many of the elderly in my family make it to their late nineties. We are allowed to eat according the dietary laws given the Israelites by God in the book of Leviticus. So, basically, SDAs eat like the Jews, avoiding unclean meat but allowed to eat many kinds of clean meat.

    As Adventists we generally end up eating a lot of simple whole foods. Olive oil is big as are legumes and nuts. My Grandfather, who hadn’t eaten meat since a teenager, recently died at age ninety eight. So, his being a vegetarian most of his life didn’t hurt him much. My Grandpa was very active, bright and lovable. He had excellent vitals..low bp and good cholesterol. He kept all his teeth, including his wisdom teeth, to the end. His doctor, and a dentist he saw five weeks before he died both just shook their heads at his good health. But, he did have osteoporosis. My Grandpa fell, walking his usual quarter to half mile walk around his nursing home, and broke his hip. He decided that he didn’t want to fight his way through physical therapy again (he had broken his hip before when he was 90 so he knew what he was up against)and so decided to die.

    I think, knowing what I do from his example and from what I’ve learned reading and researching, that my Grandpa’s bones would have been a little stronger if he had eaten some high quality, grass fed beef, venison, salmon and other “clean” high quality meats. But, for the most part, my Grandpa’s typically Seventh-Day-Adventist diet of fruit, whole grains, nuts, olive oil, legumes and other wholesome simple foods paid off in a bright and active old age. His diet was certainly a sight better than the average U.S. diet. He never had a weight problem and was undoubtedly blessed with good genes to start with.

    Most Americans would do well just to begin eating simple, fresh, local traditional foods like humans have always done, especially prior to the 20th century. It would be better for our health and the health of the world around us. Also, since we now have lower child mortality in western nations thanks to immunization and other modern medical intervention, maybe we should consider having fewer children. Many “primitive” people deliberately spaced their babies (American Indians did) due to the pressures of their nomadic lives and for the health of the mother and subsequent children. If we are going to aim to live longer, smarter, better lives perhaps there should be fewer of us on this planet?

    Patty Lynn wrote on December 10th, 2011
  6. Hi!

    I enjoyed this posting and also shared it with my fans on facebook!

    Thank you!

  7. this site has to much info really bad? (:

    sahil wrote on March 12th, 2013
  8. Good post Mark, It begs a question to the health of the indigenous. Was their immune system so vulnerable to western disease due to a lack of fresh greens and probiotics? Thanks to the progressive and reavealing studies of our era we can evolve to a superior diet and live to be optimally healthy.

    Dan wrote on June 4th, 2013

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