Exploring the “Paleofantasy”: What Evolution Tells Us about Sex, Diet, and Modern Life

(Editor’s note: This article from a past issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)

When speaking about evolution many people tend to use the past tense, as if we’re no longer evolving, as if our species is the same now as it was during the Paleolithic period. This is false. Similarly, many people believe that in order to maximize our health and longevity, we should imitate the lifestyles of our Paleolithic ancestors. According to Marlene Zuk, a biologist at the University of Minnesota, this is also false.

There are those who have embraced what anthropoligist Leslie Aiello calls “paleofantasies” or nostalgic visions of, as Zuk writes, “a time when everything about us — body, mind, and behavior — was in sync with the environment.” In her witty and well-researched prose, Zuk debunks these pseudoscience-based conceptions and proves that humanity did not have a time like the kind depicted by these fantasies; evolution has always been and will continue to be a key player in our species’ future.

Let’s take a closer look at what she means. Contrary to the belief of many, evolution is not a linear phenomenon; there is no straight and narrow path from one point to the next. Rather, Zuk prefers to think of it as a drunkard’s walk; there are detours, sidetracks, branch-offs, and reinstatements. The course is determined by environmental input, genetic mutations and natural selection.

Among many interesting points Zuk offers, her thoughts pertaining to immortality are particularly striking. While there are many steep prices to pay for immortality — watching friends and family die, never leaving a mark, etc. — there is one price greater than the rest: In a few thousand years you will realize that you’re an antiquated model of a now considerably more advanced species. You will be shorter, slower and dumber than your counterparts, and it’s very likely that no one will want you around.

Paleofantasies shouldn’t be applied to our current lives. For one, Zuk believes that relinquishing our grasp of them will allow us to live better by paying attention to how our bodies respond to healthy food and balanced diets, rather than going for any one extreme. Secondly, it may help us be aware of the type of footprints we leave on our environment, since we change it much like it changes us. Thirdly, hopefully we will strive for a better relationship with other organisms by letting go of our imagined monopoly over evolution if we accept that we all evolve in order to coexist.

Brain World had a chance to speak with with Zuk, author of “Sex on Six Legs: Lessons on Life, Love, and Language from the Insect World,” and “Paleofantasy: What Evolution Really Tells Us About Sex, Diet and How We Live.”

Brain World Magazine: Why did you embark on the very long endeavor to write “Paleofantasy,” which is about evolution and how we misperceive it?

Marlene Zuk: I suppose a lot of it came out of the long-standing frustration dealing with people who misunderstand it. At some level [evolution] is complicated, but, on another level, it really isn’t. And yet it seems like there is so much around us about how we can and can’t learn things from our ancestors, or from our evolutionary history that’s just misplaced. So scholars need to set the record straight and say, “No wait, here, this is how it really works!”

BW: Do you feel there are a lot of scholars trying to do this, or is there a certain amount of intellectual boxing-in?

MZ: I think there are a lot of scholars trying to do this but I think it’s not always easy. The material is complicated; I relied a lot on my colleagues and people who were doing some of the research. I was actually just telling someone that more than anything else I’ve written, I really had to tear myself away from continuing to do the research because new and exciting things are happening everyday — where you look at a journal and you say, “Ooh, I should really include that article,” but then again, the same thing will happen tomorrow, and the next day, and the day after that. So at some point you have to say, “I’m done.” I had to stop so that my editor could work; but I think that there are a lot of people trying to convey this.

BW: Your background is in biology, evolution and also behavior. In the last 3,000 years, people have assumed that evolution’s stopped, but you showed that in smaller organisms, evolution can occur in as many as a few generations back. As a behaviorist, how do you explain it?

MZ: It has been a really big thing in behaviorism. OK, people are alright with the fossils, and we can see that a horse’s bone changed over time because we have the different fossils from different periods to prove it. But behavior is so flexible to begin with that it’s not fossilized in any way. So how can you talk about behavior evolving the way you talk about traits like leg length evolving? When you get down to it — this has been a question that people who study animal behavior have been asking for as long as people studied animals. Behavior is a trait like all the other traits. It really isn’t any different than leg length because like leg length, it results from genes and input from the environment.

All traits, all the time, are always the result of input from the genes and input from the environment, so people will grow shorter if they don’t eat enough, but their leg length will also be determined by the genes and environmental input; there will always be an interaction there. Behavior is the same way! It may be more difficult to see and figure out — which component came from the environment and which component was the input from the genes — but it’s actually liberating to realize that it’s not any different. People ask, “How does behavior evolve?” and they ask that while throwing a stick for their dog that a few thousand years ago was an animal that would tear your arm off if you were in the same room with it. So, you’re going to tell me that behavior doesn’t evolve? Of course it does! We made it evolve, at least in our pets!

BW: Your argument is really compelling but still, half of the American population does not believe in evolution!

MZ: Believing in evolution is somewhat of a strange way to put it! I mean whether you believe in the germ theory or not, you’re still going to get sick with the flu; your belief is immaterial to the germ theory belief.

And then there is the whole argument about how scientists use the word “theory” differently from the rest of the general public. To me, this is almost all part of a great lack of understanding of and an appreciation for science, and for how much it explains about the world. To scientists, the evidence is overwhelming … Evolution and natural selection is just as well-supported as any other scientific theory we have. I think that people are stumped by the idea that, for however long, it’s not just fashions that are going to be different; our core would be different because evolution is constantly happening. I think it really is hard to think about it.

(Editor’s note: This article from a past issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)



  1. Finally Zuk’s contribution is some significant debunking of the whole paleo-diet fantasy. Another name that these dieters have claimed for their view is the so-called ‘evolution diet’. This is because it is based on assumptions of perfect adaptation by paleo man to their presumed food. This assumption as Zuk argues is spurious. Perfect adaptation is to be invoked only in some Garden of Eden. Further the assertion that our genes have not had sufficient time to changes ignores all that is know by the rapidity and extent that selection operates. Rather than scientific evolution as a basis of today’s paleo – dieting, I claim biblical dogma should be recognized as its inspiration. Rather than the evolution diet, a more appropriate name is the ‘creationist diet’. In this scenario, the cereal grain replaces the apple, and the plant breeder replaces Eve. Longing for Eden is perhaps a deep motivation for adherents.
    Tony Brown

  2. Alright. If I could, I’d like the discourse regarding the quick cricket evolution striken from the record as I have delved further into the phenomenon and realize that I misunderstood what the situation entailed. Apparently, this evolution involved a direct change in the biological structure of the wing itself so that it wouldn’t create the sounds that originally attracted the parasitic flies.

    Still, the Paleo/Primal style of living isn’t as regimented as perhaps Ms. Zuk is purporting that it is. In addition, there is a glowing, energetic and vital legion that not only thrive on this lifestyle ethic, but many of them drastically changed their health and well being fortunes by forgoing “modern conventional eating practices” while embracing this movement. Me? Well, I was doing pretty OK before I actively began practicing the Paleo thing but for how long would I have remained cavity free, doctor’s office free, obesity free, etc. whilst living that way? Who knows? There’s no telling how long I will be able to stave those maladies off even so but the smart money is to do it by giving my body what it needs…what it has been evolutionarily predisposed to accept and process.

    Sure, there could be a time down the line ..who knows when.. where the human digestive and endocrine systems will be able to handle partially hydrogenated oils and the phytic acids, gluten and lectins of grains, but do you want to be the one to take that evolutionary road?

  3. As a corollary to the preceeding post, I might conceed that in the cricket example, perhaps it is that the cricket has no willful say in whether it chirps or not and rather, that it just does so out of hereditary. After all, how could a cricket understand that he is evading a “parasite” by not making his typical mating noise? Well, I suppose that would depend on how large and evident the parasite was to the cricket. Furthermore, I would find it difficult to comprehend the rate of “mute” crickets that would be needed to be born within that five years span in order for them to totally change their innate behaviors. Also, Where does that leave all the previously loquacious crickets as compared to their newly and rapidly evolved bretheren? Extinquished, that’s where. So, which of us really wish to take on the role of “extinguished less fortunates” as we strive to evolve to the plight of the Hawaiian cricket parasite that is our messy assimilation into the Standard American Diet? Let me tell you, there will, as has been, a lot of collateral damage. Which begs the question: why do it? At least in the case of the expatriate Hawaiian crickets, they had no choice in the matter…where our diet is concerned, we have much more lattitude.

  4. I would, even in my untrained, unpedigreed understanding of evolution, take exception with the assertion that behavior is a trait along the same lines as bone shape, hormone function, eye color, etc…behavior, while predisposed, is perhaps the only trait that can be altered by the organism itself. Therefore, whilst the cricket that isn’t indigenous to Hawaii can silence it’s inate chirping within a period of five years, it cannot change anything about it’s physiology. That silencing of the chirping trait isn’t so much evolution as it is “learning.” Now, that in and of itself, I would agree, is an adaptation and thus, evolution but it is a willful adaptation and not a physiological one like say, if that cricket ended up being able to subsist on pineapple stems even though such vegetation was not only foreign, but toxic to the cricket.

    Yes, there are many people with the gene to enable them to break down starches but there are many without it. The same goes for the lactase enzyme and it’s hetergenous appearance in the human populace…physiological evolution takes time…and this doesn’t mean just simply tens of thousands of years. You may be the sort of person who can do well ingesting all sorts of starches and lactose but that harldy means that you shouldn’t experience the benefits of a paleo lifestyle. If anything, the idea behind the nutritional segment of this lifestyle movement is, “when in doubt, leave it out.” The doubt is found by looking no further that clinical studies that link prolonged high serum insulin with many of today’s “diseases of modern living.”..among other things. Keep in mind, for the Paleolithic- Stone Age,-Caveman, whatever you want to call who we are all derived from, change came at a much slower rate that what we have experienced nutritionally in just the last 100 years alone. So evolution chugs on, sure…this is never in doubt. But how different are we physiologically from him, really?

  5. Ok so the article clearly establishes that the author is a biologist that excepts evolution.

    Where’s the bit that she busts the myth of the her so called “Paleo Fantasy”?

    Sure, the flu virus can mutate and evolve quickly, but the author has to show how we humans evolved quickly over a couple generations to sitting all day long and eating chemical laden processed foods.

    Then also explain the sudden health epidemics of diabetes, heart disease, obesity, depression, gastrointestinal diseases etc.

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