Human Lifespan: Another Potential Link to Early Fat & Meat Scavenging?

Interesting article from reader Jim.

Meat may be the reason humans outlive apes

Even hunter-forager humans have twice the life expectancy as wild chimps

Genetic changes that apparently allow humans to live longer than any other primate may be rooted in a more carnivorous diet.

These changes may also promote brain development and make us less vulnerable to diseases of aging, such as cancer, heart disease and dementia.

Chimpanzees and great apes are genetically similar to humans, yet they rarely live for more than 50 years. Although the average human lifespan has doubled in the last 200 years — due largely to decreased infant mortality related to advances in diet, environment and medicine — even without these improvements, people living in high mortality hunter-forager lifestyles still have twice the life expectancy at birth as wild chimpanzees do.

Now, we understand that chips cooperatively hunt, capture, and rip their prey apart limb-from-limb to great tribal fanfare and meat loving…

Here’s one that shows their hunting tactics from above, via infrared.

So what gives, then? Well, perhaps it’s because bi-pedal hominids began using stone tools upwards of 2.5 million years ago and probably longer. In so doing, they were able to scavenge the high density nutrients (fats, mostly) in bone marrow and brains, inaccessible to carnivores.

Then, as Max Kleiber showed in 1947, humans, chimps and virtually all animals follow a linear function of mass to metabolic rate.


So, essentially, all animals that weight the same have the same metabolic rate. And in comparing us to chimps, we find that all the major organs have the same metabolic cost. What’s different is our brain size vs. gut size. From the article:

The oldest known stone tools manufactured by the ancestors of modern humans, which date back some 2.6 million years, apparently helped butcher animal bones. As our forerunners evolved, they became better at capturing and digesting meat, a valuable, high-energy food, by increasing brain and body size and reducing gut size.

Now for my first complaint: how come on the one hand it talks about butchering animal bones, leading to capturing and eating meat, yet no mention of fats? What’s inside bones is extremely high in fats. Why not acknowledge that?

At any rate, I’ve posted on Kleiber’s Law and the Expensive Tissue Hypothesis recently, for those desiring more in-depth:

And if you want to really dig deep into it, see Dr. Mike Eades post, Are We Meat Eaters or Vegetarians?

Then we advance to unlock another piece of the puzzle from the original article cited.

Over time, eating red meat, particularly raw flesh infected with parasites in the era before cooking, stimulates chronic inflammation, Finch explained. In response, humans apparently evolved unique variants in a cholesterol-transporting gene, apolipoprotein E, which regulates chronic inflammation as well as many aspects of aging in the brain and arteries.

One variant found in all modern human populations, known as ApoE3, emerged roughly 250,000 years ago, "just before the final stage of evolution of Homo sapiens in Africa," Finch explained.

Well that’s all well and interesting, but I’m not sure how well that hypothesis (that ApoE3 arose primarily in response to parasites from uncooked meat) would stand if it turns out we began cooking much, much earlier (Is It The Meat, or Cooking The Meat?), maybe even at the advent of homo Erectus 1.8 million years ago. We do know from even modern hunter-gatherers that cooking vessels aren’t needed, that the meat is often just tossed in the fire and retrieved to eat. Speculating, could we have gotten a taste for cooked meat very early, say, from scavenging meat burned during a quick forrest or brush fire ignited by lightening?

But I’m getting a little suspicious. Is there a "meat is inherently unhealthy" bias, and we had to evolve ways to not die from the very thing that they just claimed made us human in the first place…? Does this not strike you as somewhat circular? I mean, it couldn’t possibly be that we evolved to live longer than apes naturally (all else remaining equal) because of numerous factors, evolutionary pressures, surviving great odds against us, and/or that there’s one hell of a lot more bioavailable nutrition in a diet of cooked meat, fat, vegetables, fruits & nuts than, say, cellulose?

Is this yet another example of unbridled reductionism — that it’s necessary to find a single magic switch in a gene that protects us from awful meat & animal fat? Well, I suppose that’s where you have to look if you accept the premise.

So now for the obligatory anti-meat & animal fat part, signaling the bias I was beginning to detect.

"I suggest that it arose to lower the risk of degenerative disease from the high-fat meat diet they consumed," Finch told LiveScience. "Another benefit is that it promoted brain development."

Curiously, another more ancient variant of apolipoprotein E found in a lesser degree in all human populations is ApoE4, which is linked with high cholesterol, shortened lifespan and degeneration of the arteries and brain.

Yep, that’s what it looks like to me. The very thing that drove our evolution profoundly forward is a-priori unhealthy and instead of wiping us out, we eventually developed a coupla genes that keep us alive (and for longer than our ancestors!). But, if I get the implication right, do lower your meat, animal fat consumption, and of course, watch your cholesterol!

That’s my take, anyway. Anyone see it differently?

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  1. John Campbell on December 16, 2009 at 15:04

    Yes Richard I think you are right. The anti-fat bias is as strong as the thought that the earth was the center of the universe held centuries ago. This perverse axiom in health and nutrition forces otherwise intelligent scientists to come up with convoluted explanations to protect that central axiom.

    Humans fall in love with their axioms and cannot imagine examining them. Scientists are human like the rest of us, except that most of them have invested much more of their lives in their axioms. Sigh. The wheels of progress can move slowly, but a tipping point will come. Humans have come too far to remain ignorant forever.

    I can hardly wait to go into work tomorrow and tell my staff the result of my recent blood tests – I mentioned them in another comment here. Eating paleo with lots of fat for about 20 months – yum – triglycerides now less than a 1/3 of several years ago, HDL up 50%, LDL up some with lots more large particles. And after over 20 years of elevated liver enzymes, the levels are down 75% and now normal. Non-alcoholic fatty liver resolved by eating paleo. My staff could not ignore the changes in my appearance, but they were convinced my blood would reveal the folly of my ways. He who eats fat laughs last – but I would like to see them join me. I take no pleasure in seeing others eat their way to poor health.

    Keep up the good fight my friend. You are helping to save lives here. Fat rules – long live the king.

    • Richard Nikoley on December 16, 2009 at 16:59

      I saw that comment earlier and was tempter to toss it up into a full post.

      How about you email me with the reaction and we’l see if we can make a post of it. I think the “reader results” posts are not only the most popular, but effective.

      You too, can save the world. :)

      • John Campbell on December 16, 2009 at 18:50

        Sure – I am also interested when my family including two brothers-in-law taking Lipitor react.

  2. Icarus on December 16, 2009 at 15:30

    Yep, I was annoyed by the anti-fatty meat bias too. It’s annoying that researchers seem to try to find the most obscure reasons to label meat as unhealthy – if it isn’t the sat fats, then it’s the hemoglobins and myoglobins, or now (apparently) it’s the apolipoprotein Es. Yeah, whatever. It’s funny, though, that the “nomg meat causes degenerative diseases!!” was followed by a diminutive “…oh yeah, meat also allowed the large increase in brain size compared to chimps.” But no matter, it’s GOT to be bad for you somehow. Then there’s the emphasis that everyone puts on proteins over fats; how do they think the brain got so big if it is composed primarily of both protein AND fat – specifically, in large part DHA and EPA? Both fatty acids are found in animal fats, and are difficult to convert from ALA. Hmmm. I guess our ancestors ate a lot of seaweed – you know, the seaweed that is abundant in Central and Eastern Africa, yuk yuk.

    Personally, I don’t like the cooking hypothesis much at all. It seems to be an attempt to take away from the importance of meat, with not enough evidence to back it up. Note that parasites are not always bad; their general goal is to NOT kill their host. Even if our ancestors enjoyed eating the occasional lightning-struck corpse, I doubt this would have been anything more than an occasional treat until they actually learned to control fire. I’m thinking this is most comparable to honey – a rare treat that wouldn’t make up a significant portion of the diet, not enough to force genetic change in any case. The fact that there are human-specific tapeworms (in beef, pork, and I’d assume wild boar and the aurochs) would suggest that there is a history of co-evolution between humans and these tapeworms – in other words, that humans ate a lot of raw (red) meat for a very long time.

    Also, the thing to remember with chimps is that they seem to value meat (a lot, if that video is any evidence) but that in their environment – tropical trees – fruit, leaves, insects and other such easy pickings are more abundant than animal matter. Thus, there is not enough pressure on chimps to force them to eat primarily meat. Contrast this with African grassland, where tough roots and (inedible) grass are the main plant items on the menu, while meat is abundant, including scavenged fats from bone marrow and brains (which non-human animals cannot access.)

    • Richard Nikoley on December 16, 2009 at 17:01

      Thanks. Awesome comment. I too am skeptical of the cooked meat hypothesis, but it works for paleo either way, as I see it.

      So, I like to keep it out there. Let’s see what becomes.

      • Icarus on December 20, 2009 at 19:36

        I agree. I’d say cooking has been around for at least a few hundred thousand years – possibly as long as H. sapiens. I’m just skeptical about pushing the date back any further than that without really good evidence.

        Personally, I like the flavor, texture, and warmth of rare-ish cooked meat best, but I have no qualms with eating carefully sourced raw meat, and I prefer fish to be raw for some reason. I guess I’ve just gotten used to eating sashimi.

    • anand srivastava on December 17, 2009 at 04:20

      The cooking hypothesis might be required to explain the very high number of AMY1 genes that we have. It is expected that we obtained them around the time we became Homo Sapiens ie 200,000years. This could be explained more easily by eating tubers but requires that we used fire regularly. There are not many other easily available starchy things that also provide significant amount of calories.

  3. Alex Thorn on December 16, 2009 at 16:07

    The major flaw I see in this article is the preoccupation with parasitic infection from raw meat. Humans are just as likely to ingest parasites from contaminated water and fruits and vegetables. In fact it is more likely that we would get infected from eating raw contaminated fruit and vegetables because the parasites are usually at the ‘cyst’ stage of development and this protects the larvae from destruction by the digestive acids and enzymes. When they pass to the lower intestines the more alkaline conditions allow the cyst wall to break down and the parasite is free to swim where it likes! Adult parasites in animal tissues are more likely to be chewed and or killed by stomach acids along with the host meat! However, I would much rather cook my meat than eat it raw anyway – better to be safe than sorry!

    • Richard Nikoley on December 16, 2009 at 17:06

      The interesting thing about parasites — or should we really say, symbiots — is the evolutionary possibility that they have domesticated us!

      You can regress that, too. In evolutionary logic, no organism is any more important than another. It’s all a race to thrive, and bacteria & parasites seem pretty damn good at it.

      Perhaps we have simply been fooled into believing we’re the masters — all the while the bacteria, parasites & symbiots thrive & evolve.

      Then there’s the cockroaches…

      • Alex Thorn on December 17, 2009 at 05:57

        I would differentiate between parasites and symbionts (or symbiotes): Symbionts usually have a mutually beneficial relationship with the host whereas parasites usually have a destructive effect on the host. It is believed that the mitochondria we have in our cells were originally separate organisms that formed a symbiotic relationship with the host cells they invaded (they could use oxygen to make energy whereas the host cells could not and the host cells’ anaerobic respiration provided by-products that the aerobic mitochondrial cells could use). This became such a mutually beneficial relationship that they eventually became one integral cell.

        Parasites, on the other hand, only require the raw materials and energy provided by the host to enable their own development and procreation. Larvae are then usually passed out in the faeces of the host and cycle begins again when another animal ingests these larval forms. They don’t tend to give anything beneficial back to the host and may actually carry other pathogens within them that prove toxic to the host in some way.

        However, you have to marvel at the intricacies and interdependence of life both on the macro and micro scale!

      • Webster Webski on December 17, 2009 at 06:09

        I read some time ago that parasitic worms in the gut lead to decreased general body inflammation and that it was “The War on Parasites” in the beginning of the last century that has lead to the spike of a host of autoimmune diseases like asthma etc. One experimental technique for curing-alleviating asthma is a controlled infestation with a particular species of worms. Come to think of it, it’s hard to imagine a paleo man WITHOUT some population of worms and other parasites. It just might be that they (at least some of them) play a very important role in human health just like gut bacterial micro-flora…

      • Alex Thorn on December 17, 2009 at 07:53

        This was the (indirect) subject matter of a recent episode of ‘Fringe’. However, Cordyceps Sinensis is not a worm it is a fungus. The fungus parasitically devours a moth larva while it is hibernates beneath the soil. The fungus then forces its way up to the surface so that it can spread its spores. The fungus takes on the shape and features of the caterpillar it devoured so looks like a ‘worm’ but it is not.

        I know it was once fashionable for people to deliberately infect themselves with tapeworms in the belief that it would allow then to lose weight – and when I was growing up it was often said (of someone who ate like a horse but remained stick thin) that they must have a tapeworm!

        “There is evidence of advertising, from the late 19th and early 20th century, hawking “sanitized tapeworms” to help women maintain a slim figure. Whether the pills sold actually contained tapeworms or whether women actually ingested them hoping to acquire a tapeworm is difficult to verify. Such a pill would likely contain the cyst part of the tapeworm’s lifecycle, but one would imagine that cultivating a large supply of these would make for a rather unpleasant day’s work. It seems unlikely, but there’s also a good chance that somewhere in the long, strange history of humanity, someone somewhere did try using a tapeworm to lose weight. So, the answer to the question, “Did it happen?” is most likely yes, but it was probably never widespread.”

        However, infection with a tapeworm can lead to malabsorption and malnutrition in the host especially if underfed, so it would not very beneficial for long-term health.

        “Cysticercosis, the condition resulting from tapeworm hexacanths burrowing their way into your bloodstream, is not pleasant. The cysts can end up pretty much anywhere in your body, including in your eyes or your brain. The cysts sometimes grow, and they inflame the surrounding tissue. The resulting pressure can cause temporary symptoms or permanent damage, including blindness, brain damage or even death in some extreme cases.”

      • Webster Webski on December 17, 2009 at 09:05

        Also here:

        I can’t seem to locate original studies at this point..

      • damaged justice on December 17, 2009 at 09:48

        I knew this reminded me of something:

        “How to cure your asthma or hayfever using hookworm”

      • Alex Thorn on December 17, 2009 at 10:39

        Ah yes! This was the actual worm being alluded to in Fringe it would seem.

        Very interesting hypothesis. I’m not convinced by the ‘hygiene hypothesis’ for auto-immune diseases and allergy, though – it seems to better fit a ‘lowered’ immunity rather than a ‘hyperactive’ one.

        I much prefer the theory put forward by Loren Cordain, among others, who posits that certain lectins or plant/grain based proteins, like wheat germ agglutinin, get transported through the gut wall intact where they are targeted by an immune response.

        Unfortunately many of these foreign proteins may have a similar structure to native proteins and so the immune response becomes sensitised to our own tissues, which it attacks with the same vigour as the foreign invading protein.

        It is much the way Guillain–Barré syndrome, an auto-immune disorder of the peripheral nervous system, can be triggered by an acute immune response to infection with the Campylobacter jejuni bacterium, among others. In this case the core oligosaccharides of Campylobacter jejuni lipopolysaccharides (LPS) display molecular mimicry with gangliosides. It is the gangliosides, compounds naturally present in large quantities in human nerve tissues, that are targeted by the immune system in Guillain–Barré syndrome

      • Webster Webski on December 17, 2009 at 08:57

        Yep, when I was growing up in Russia I heard similar “old babushka’s tales” about thin people who ate a lot. I also understand that there may be severe side effects ( in some cases deadly) from parasitic infestation by certain worms. What I was referring to though was a fairly recent research on the influence of some worms on inflammation in human body and autoimmune diseases, see for example here:
        All this is basically related to the so-called ‘hygiene hypothesis’, probiotic supplementation and “Grok eating dirt all the time”!

  4. Don Matesz on December 16, 2009 at 17:53

    “Why not acknowledge that?”

    I think we have a ways to go before any pop writer will feel comfortable saying anything that would suggest that eating animal fats is beneficial.

    “I suggest that it arose to lower the risk of degenerative disease from the high-fat meat diet they consumed,” Finch told LiveScience. “Another benefit is that it promoted brain development.”

    I don’t find this in the least convincing. Degenerative diseases would occur long after reproductive years. The Apo would have to pre-exist (before meat-eating increased), then environmental circumstances would have to favor the survival and reproduction of hominims with the Apo genes. He talks as if the Apo arose after the fact, to prevent diseases occurring as a result of meat-eating.

  5. Uncle Herniation on December 16, 2009 at 18:16

    Eating ANYTHING is going to cause some disruptions to cellular functioning. Some things we eat promote inflammation, others reduce inflammation. There are a lot of other things that happen, too (to put it simply). If you can name one substance we ingest that has absolutely NO impact on our physiology, please do so, because I’d love to get a good laugh for the night.

    If you accept that basic premise, then it’s not irrational to suggest that we evolved biological, physiological, or genetic mechanisms to protect us from our environment, to some degree. The article also compares humans to chimps, and one key difference is meat consumption. Another key difference is ApoE genotype. Again, these are facts and are used to support a logical argument.

    The author is proposing a theory based on the fact that the e3 allele appears to have evolved later in our phylogeny than the e4 allele. It is also clear that the e3 allele allows us to age more successfully, well past our child-rearing age. To successfully argue against the author’s claims, the points in this paragraph need to be addressed in an evolutionary context. When talking about parasites, for example, we are using today’s knowledge and applying it to evolution over millions of years – remember, the parasites you think you know all about today also evolved over that same time period. Can you confidently apply your knowledge of today’s microorganisms to microorganisms millions of years ago?

    It’s great to be skeptical, but skepticism only moves knowledge forward when a) it provides evidence that refutes a previous theory and b) it gives rise to new theories that can be tested empirically. I’m not really getting that here.

  6. Patrik on December 16, 2009 at 20:44

    This is a classic epistemology problem. Hyper-smart people aren’t aware of their own biases or the very assumptions they are predicating their analyses on.

    Here the assumption/bias is “Meat is bad.” Let’s just make the facts fit the hypothesis.

    BTW as someone who studied anthropology, both cultural and physical, I am of the opinion that the “Meat is bad.” implicit assumption grew out of the hippies/Marxists involvement in the academia/anthropology.

    If anyone recalls what sort of hysteria came about within the anthro community when it was first shown that chimps were anything but peaceful vegetarians.

  7. Eegah! on December 17, 2009 at 01:37

    Chimps don’t just hunt monkeys, they’re quite prepared to indulge in a little cannibalism. If meat is murder, then the following is definitely a war crime:

    • Nige on December 17, 2009 at 09:34

      We need to be more like Bonobos.
      C’mon ladies! If you want men to do the chores/not start a war/w.h.y, you know what you have to do! ;-D

  8. Aaron on December 17, 2009 at 13:50

    There is no doubt that humans can thrive on a high fat/meat based diet with vegetables/fruit thrown in for seasonal variance. After you get older, it gets a little tricky, most will live longer because of a reduction in protein and caloric intake. Carbs or fats don’t matter as much. Our FOXO genes are already turned up. I think you get rid of any potential problems (such as heart disease) on a high fat diet by reducing meal frequency or fasting.

  9. AllenS on December 18, 2009 at 07:36

    Richard Wrangham, in his book “Catching Fire: How Cooking Made Us Human”, presents a very persuasive argument that the softening of cooked foods, including meat, increases its nutrient availability to the digestive system. And it is this that allowed hominid digestive tracts to shrink and our brains to enlarge. The parasite hypothesis sounds pretty far out there.

  10. Weekend Link Love | Mark's Daily Apple on December 20, 2009 at 07:04

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  11. Vivian on December 20, 2009 at 09:44

    Oh, hey! I just learned about the apoE genes in my genetics class this past semester. The E3 and E4 alleles are actually masked by epistasis in the presence of the LDLR1 allele that codes for the LDL receptor so that if you have the LDLR1 allele, the apoE E3 and E4 alleles don’t affect your serum LDL cholesterol levels differently. If you have the LDLR2 allele, then this difference between the effects of the apo E3 and E4 alleles is significant.

  12. Juan on December 20, 2009 at 14:03

    Hi all (first post here),

    Great blog, Richard, and great host of commenters.
    I haven’t read the article, so cannot comment on it, per se, but I feel your take on it is good. I cannot put my finger on it as I write, but I understand that there are populations of chimpanzees whose meat intake is around 23%. Far from the 2% often stated by vegetarian/vegans. I don’t know where either number comes from, but I suppose if they are both “correct” then it shows simply a local variation adapted to local availability.

    However, just to throw something else into the mix; whenever we see modern people eating raw meat, such as the Inuit, or the various Siberian people eating caribou, Africans, etc, it’s never especially evident from the documentaries or the articles that any of these groups get sick from (alleged) parasites with any regularity. Perhaps they do, I don’ t know. But, be that as it may, there are indeed some nutritional regimens around that advocate a raw meat diet. In these groups it is felt (no “science” to back it up; just anecdotal) that healthy raw meat will not make us sick, nor will eating so-called “high meat”, or meat that has gone bad.
    It is thought that if cooked meat is left to go bad however, then yes, THAT will make us sick. Take for example the meat that is hung (properly) by a butcher for around a month; it doesn’t make us sick, it gets better! I’ve personally eaten lots of raw meat in the past year, including liver and chicken, with no ill effects at all. (So far as I can tell.)

    Yesterday I watched a brief documentary on a modern-day Inuit group killing and butchering a walrus. It was amazingly gory but somehow awesome, too. They cheerfully ate raw bits and pieces all the while as they busily prepared the carcass to take back with them. Not an ounce was wasted.

    Anyway, all that for what it’s worth and as food for thought (pun intended).

  13. Juan on December 20, 2009 at 14:07

    Oops, my second paragraph reads as though there are various Siberian people who are eating Africans!!! I should have just said “…modern people eating raw meat, such as the Inuit, or the various Siberian and African peoples who do the same.” Yeesh …editing!

  14. Annette Huang on December 20, 2009 at 17:29

    Richard Wrangham was interviewed on Radio New Zealand National ( this last weekend. A good canvass of his book, but to me the glaring omission was any mention of the healthy fat consumed over millennia. For reference to the appeal of marrow in bones check out Tom Naughton’s latest post:

  15. […] two articles above and the actual paper. Nowhere in any of them will you find a single reference to meat as our prime evolutionary driver. That's quite an omission that to me calls into question bias, if not outright ignorance. I quote […]

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