Evolution’s Weighty Anchor

» May 30th, 2014

There are few ambitions more audacious than trying to convince someone to change his diet on ethical grounds. Eating is, at its core, an act of personal intimacy and nobody really wants to be instructed on how to be intimate. We like to think we’ve got that one figured out.

This point is one that a lot of animal advocates forget when we present our case with what seems like airtight moral logic, only to then be ignored or scorned by folk who are perfectly happy with their BLT and BBQ, thank you very much.

It drives animal advocates a bit nuts. When we congregate we will often say, somewhat plaintively, “when will people realize what they’re doing to animals? When will change happen?!” Brows furrow. Heads shake in frustration.

The problem with the question, of course, is that it rests on the flawed assumption that humans respond to moral logic with appropriate behavioral change. Not only is this wrong, and not only is the moral logic we espouse rarely as persuasive as we think it is, but the truly daunting fact of the matter is that, in politely asking humanity to stop eating animals, we overlook how eating animals is more than a cultural choice. It’s a biological act rooted in our deepest eco-evolutionary past.

Now, that doesn’t make it right (as readers know I’m well aware). But let’s take this seriously: a couple million years of hunting and gathering, not to mention the adaptation of the human brain to life on the African savannah, makes the carnivore doet a pretty freakin’ tenacious habit

Three aspects of our evolutionary legacy strike me as particularly relevant to the claim that, when it comes to eating animals, the past has a commanding and assuredly long-term hold on the present. In this post, I’ll note just one.

It has to do with the experimental backstory to the human carnivore’s diet. As a species, hominids did not burst on the scene and start eating a standard diet appropriate to their needs.

The standard diet appropriate f0r hominids (and homo sapiens) in the pre-agricultural era was forged through endless and terrifying trial and error. Plants and animals were tested, accepted, rejected. They were savored, flavored, regurgitated. People routinely died because of poor dietary choices. Others thrived.

In other words, an essential part of becoming and being human involved testing the natural world to see what would keep us in the game. A tremendous amount of evolutionary energy was invested in this process, one that, by virtue of hundreds of thousands of years of accumulated assessments of what “works,” made eating at least some meat central to being human.

That fact might run counter to contemporary animal ethics, but it’s a heavy anchor to pull up all at once.



30 Responses to Evolution’s Weighty Anchor

  1. John Maher says:


  2. Jerry Friedman says:

    James, I hold the opposite thesis. Our ancestors from the time of dinosaurs ate insects, but quickly adapted to a plant diet as they sought refuge in trees. Our line has been eating leaves and fruits for over 60 million years. Fossil and stone tool evidence suggests that our line has been eating scarce meat for 3.4 million years and plentiful meat for 50,000 years. The heavy anchor to pull up is abandoning our plant-eating roots, not the more recent taste for meat.

    See https://www.youtube.com/watch?v=eCbPDld4-l0

    • Sailesh Rao says:

      Right, it’s just different story-telling. In point of fact, diets have changed tremendously just over the last 50 years – for the worse, from a health, animal rights and environmental point of view and for the better, from a corporate-industrialist, planet-gouging, profit-making point of view.

    • Kimberley Mae Richardson says:

      Great reply Jerry.

  3. Elaine Livesey-Fassel says:

    Understood completely and appreciate your articulation – always invaluable input! I am often reminded by some that it was because of our eating animals that OUR brain grew ( while obviously NOT our empathy/compassion for those exploited and consumed)! All life’s actions and choices need examining from time to time and this particular choice is vital to we who question its relevance!

    • Kimberley Mae Richardson says:

      I don’t believe that our brains grew because of eating animals. That is a very convenient “excuse” for compassionless meat eaters. Don’t encourage them.

    • Jerry Friedman says:

      The weight of the evidence is that eating animals did not cause the human brain to grow, and no argument exists that makes it likely. The human brain most probably grew because of social development among pre- and early humans. Please see the link I posted above, which I post here again: https://www.youtube.com/watch?v=eCbPDld4-l0

    • The actual hypothesis was that nature selected for big brains in hominids, which forced a dietary shift to including more calorie-dense food sources.

      In other words, big brains led to (more) meat-eating, not the other way around. Carnists and paleos always get this backwards.

      • Jerry Friedman says:

        Humane Hominid, that sounds like the Expensive-Tissue Hypothesis (1995). This hypothesis does not propose a mechanism, but only a correlation, between brain growth and gut shrinkage in hominins (human-line of apes) compared to hominids (humans and nonhuman apes). While it claims eating meat was necessary for its fat calories, it dismisses *without rationale* other calorie-rich foods especially cooked foods–cooked tubers provides more calories than cooked meat. It also overlooks other correlations: only one large-brained mammal (bottlenose dolphins) requires meat; carnivores generally do not have large brains. For the Expensive-Tissue Hypothesis to be right, it means that evolution works differently on humans than the rest of the animal kingdom.

        Rather than repeat the hypotheses of carnist researchers, I recommend you read “Catching Fire” by Richard Wrangham and “Man the Hunted” by Donna Hart/Richard Sussman. These researchers might also be carnist but unlike the Expensive-Tissue Hypothesis researchers, their carnism does not affect their argument.

        • Yep, read’em both a while ago. Point of correction, though: the ETH does not discount other sources of calories. The original paper by Aiello and Wheeler specifically listed meat, tubers, fruits, and/or oil-rich nuts and seeds as potential sources of the requisite extra calories. And to be fair to the authors, their hypothesis was proposed decades before anyone started thinking that cooked food was a key component of encephalization.

          The real shortcoming of the paper (in addition to what you already pointed out) was that it relied on a phylogenetic analysis of the hominid fossil record that’s no longer valid. Specifically, it assumed that paranthropines were an ancestor clade to Homo, rather than a sister clade. This assumption created two sudden spikes in brain size over time; but if we correct for current phylogeny, then these spikes disappear, and brain size progression becomes linear rather than punctuated… and the whole need for something like the ETH disappears.

          Also, the author’s measurements relied on total organ mass rather than fat-free dry mass, and didn’t account for mucosal absorption surface area of gut mass, which is what would have really counted.

          That said, though, it’s unfair to the authors to say they focused on fat calories in meat. They didn’t, really; that’s just bit of pop evo-woo read into it by paleos and other carnist apologists.

          • Jerry Friedman says:

            HH: While I agree with and enjoy almost everything you claim, I disagree on this, “The original paper by Aiello and Wheeler specifically listed meat, tubers, fruits, and/or oil-rich nuts and seeds as potential sources of the requisite extra calories.”

            Aiello and Wheeler give marginal mention to non-meat. The entire article emphasizes meat. Most telling is their abstract that asserts meat–nothing else–was critical for human brain growth. The authors wanted their readers to believe meat was the cause. Further, Aiello in later interviews and manuscripts, defends meat as the cause. I believe their mention of tubers, etc., in ETH were obligatory to mention, but that the authors did not otherwise want to mention.

        • Jerry, I guess it’s a matter of interpretation. I’ve read Aiello’s & Wheeler’s paper dozens of times, and it might just be my confirmation bias at work, but I’ve always taken their tone to be that they considered meat the most likely source of the needed excess calories, given the assumed realities of life on the Pleistocene savannah, but not as a necessary component of their hypothesis. I agree, they seem to have mentioned non-meat sources as an afterthought, but I think they did it to emphasize that their hypothesis was “reliable excess calories” rather than “meat was magic.”

  4. Kimberley Mae Richardson says:

    I don’t know why you are offering ammunition to the carnivores James. Especially because you are only espousing a hypothesis. Veganism today is not only an act of compassion but ALSO a very distinct survival strategy for the human species. Why waste valuable energy and thought on apologism for carnivores?

  5. For vegans, the homologous weight of suffering among fellow vertebrates outweighs our species’ more recent eating habits.

    • Mountain says:

      That blog post was a very enjoyable read, and yet completely irrelevant. The author (Rob Dunn) used “vegetarian” to mean animals that eat substantially more plant matter than most humans, but still consume other animals on a regular basis. And with that, Dunn’s claim disintegrates into nothingness.

  6. Ellen K says:

    “eating at its core” is actually about survival. Beyond that, ok, intimacy maybe but probably more pleasure, filling or masking emotional hungers, love, self-medicating, validating identity, custom/habit, etc with a heavy dose of Doug Lisle’s pleasure trap. These collectively weigh down the anchor more. Regardless, point taken: eating lies largely out of reach of pure reason and logic, and effective advocacy generally needs to employ other tactics.

    “biological act” or “tenacious habit”? former suggests something on the road to necessity, the latter optional choice.

    Sure, “some meat” is part of evolution, but how much and what kind? (Shouldn’t sincere modern paleo adherents should have their meat comprise mostly ants, termites and grubs? ) And how much weight do you want to give it anyway, i.e., need past continue to be prescriptive? (see Marlene Zuk) Agreed with Jerry, HH, et al.

    And to extend on JTM’s admirably succinct reply, most of us in this country have choice about ourselves and our actions. Lending *undue* emphasis on paleofantasies only fuels the wildly popular victim excuse – externalizing responsibility for behaviour on genes, biology, culture, etc., anything to deny agency and to justify “I can’t help it…”

  7. David says:

    This might inform the discussion as it points to differences between we humans and our closest relatives.
    At the bottom there is an addition by a “Daniel E. Lieberman, a professor of human evolutionary biology at Harvard, said he found Dr. Khaitovich’s study “very cool,” but didn’t think the results meant that brain growth came at the cost of strength. Instead, he suggested, our ancestors evolved muscles adapted for a new activity: long-distance walking and running.

    “We have traded strength for endurance,” he said. And that endurance allowed our ancestors to gather more food, which could then fuel bigger brains.

    “It may be that the human brain is bigger not in spite of brawn but rather because of brawn, albeit a very different kind,” he said.”
    Many of the adaptations of humans, like thermo-regulation by sweating, seen in only humans and horses, and endurance running seen only in humans of all the primates, could be explained by persistence hunting. This is still practised by hunter-gatherers in the Kalahari. Greater endurance could also mean greater ability to forage, but I don’t think it is either or.

    Personally I reject arguments from evolution as just appeals to nature, whether for or against. Even if there is a biological component to meat eating, the history of India shows that a culture that was heavily involved in animal slaughter in sacrifice to the gods, by influence from Jainism and Buddhism became one of the most vegetarian cultures in the world.
    I don’t believe most people would become vegan through argument. It might happen through the crisis we are headed for with climate change.

  8. stevekos says:

    I take strong issue with your assertion that meat-eating is a “pretty freakin’ tenacious habit”. I stopped eating meat about a year ago, after doing so with great pleasure for the previous 57 years of my existence, and after great personal resistance leading right up to the break. The amazing thing, to me, was that there was nothing to it. It was just a matter of coming around to it mentally. Nothing more than a decision. And since that point, I haven’t craved it and I don’t miss it. In fact, my attitude now is more, “How could I have eaten that awful stuff so unquestioningly all that time?” than, “I wish I could go back to it.”. A habit? Certainly. But a purely mental one, I say. And one that simply comes down to personal honesty. Which leads back to your other assertion, that it’s more or less futile to expect others to change based on our logic. If that’s true, then why do you even bother to write this blog? People are most capable of changing their behavior for good reason. It’s just a matter of making them see that reason. From there, of course, it remains their choice whether to be honest with themselves or not.

    • James says:

      You are referring to your own experience. I’m referring to the collective experience of billions of people over hundreds of thousands of years. Your experience, valuable as it is, does not reflect the history of humanity’s. That said, I am happy for you that the process was so easy.

      • stevekos says:

        Yes, but if, as a species, we have this weighty anchor, why did it not affect me? Am I so unique, or does the anchor not really exist? I was a dedicated eater and lover of animal products my whole life, and then I changed, simply because I came to terms with the reality of what that way of life entailed. If i could do it, I believe anyone could, if they just made up their mind to.

        • Karen Orr says:

          It sounds as if my experience is similar to stevekos’s when, at 56, I gathered information for a letter to the editor about factory farming regulations as part of my job as Water & Wetlands chairwoman for the Florida Chapter of the Sierra Club. The information I found just in the course of doing a little research for that brief letter flabbergasted me. I became vegan in short order – and with ease. That was nine years ago and never once in all that time have I desired the animal foods I’d eaten and enjoyed my entire life. I was finished with it.

          The letter to the editor:

          Get animal factories added to act, regulations

      • Mountain says:

        Individuals vary, but in my experience, people have a much harder giving up grains & dairy than they do giving up meat. So I don’t think Steve’s experience is an outlier– while people fear giving up meat beforehand, most don’t experience strong cravings afterward. Some cravings, for sure, but minimal when compared to other food groups.

        Still, I think James is right about our evolutionary heritage, but it applies to more than just meat. Our evolutionary heritage as omnivores makes it difficult (an anchor, if you will) to give up any particular food or food group that doesn’t immediately harm our own well-being. Of course, this difficulty can be overcome by culture– Jews, Muslims, Hindus, and many others have developed strong taboos against eating foods that were relatively harmless.

        • stevekos says:

          Mountain – Yes, the hard part is seeing past it. You’re so used to eating a certain way. But once you cross over, you realize it’s not the only way, and if you’re committed to your principles, it’s not really difficult to maintain it. There is a certain amount of sacrifice involved, but there are also unanticipated gratificiations.

  9. It’s not likely that we evolved to crave particular ingredients. Nutrients, and nutrient ratios, yes. But not ingredients.

    The notion that humans crave meat, or any other ingredient, because of their hunter-gatherer past is just magical thinking. The simpler explanation is a hormonal response triggered by some stimuli that reminds us of the pleasure we get from those tastes or their related activities; in that case, it’s the pleasure we crave, not the food itself.

    As animals, we’d also crave fat, salt, and sugar (nutrients, not ingredients) for fairly obvious reasons, but objectively, any ingredient containing them would do. The specific packages in which we get them are not what we crave.

    • David says:

      You might not be correct there that we don’t crave particular ingredients. Amino acids in this case.

      It was discovered back a few years ago that we have a receptor activated exclusively by glutamate on our tongues.
      Our first experience of glutamate in foods is breast milk.
      Glutamate, or umami as it’s called is also present in high quantities in aged cheeses, like parmesan, gouda, and manchego, pork especially when cured, and other meats.

      So we have a specialised receptor on the tongue, probably to encourage breast-feeding in infants, and this could explain people’s enjoyment of cheeses, and meats.
      I would agree with you that there is an element of magical thinking to meat-eating. You don’t have to dig too far to find men, particularly, see meat as somehow boosting virility. I remember some years ago a conversation with a group of Arab men who made no bones about the belief that if one didn’t eat meat one became effeminate. It is obvious in Chinese traditional medicine that the animal parts used are seen as having power that can be taken in.
      When I first gave up meat at the age of 13 in Ireland, my mother used to beg me to eat just a little meat once a week.

      So the magical thinking is certainly there, but you can’t just discount that people eat these foods and enjoy them so much that they can split off from the origin of it, and the suffering that goes to produce it.

  10. Oh, I don’t discount that people’s enjoyment of particular flavors has evolutionary origins. I just have a problem with ascribing everything to a hunter-gatherer narrative, as if human evolution began and ended on the savannah. The majority of characters we carry within us are far older than primates, and some are older than mammals.

    People don’t crave or enjoy meat because their caveman ancestors were hunter-gatherers, is my point. The hunter-gatherer phase of our evolution exploited pre-existing traits that arose much earlier, in response to very different selection pressures, and got retained because of their versatility. The traits that made good hunters came before hunting, not as a result of it.

    • Jerry Friedman says:

      And, for what it’s worth, the narrative will change further when we give proper emphasis on gathering. Now I use the term “gatherer-hunter” and no longer the carnist “hunter-gatherer.” Hunting has only been significant for the last 50,000 years or so, and even then it’s less significant than gathering.

      • Mountain says:

        Of course, many animal products were gathered, and still are throughout much of the world: eggs, insects and small reptiles, and carcasses that others killed. All of which precedes the existence of humans.

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