Note: Information about next month’s book is at the bottom of this post.
Welcome back to the Skepchick Book Club! This month we read Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live by Marlene Zuk. The author talks about evolution and the perception of how early humans lived versus the reality, and she does a fantastic job of countering the “paleofantasies” of others with science.
People who support the idea of a paleolithic diet and lifestyle (when it’s convenient for them, that is) make the assumption that humans were, at one point, perfectly adapted to their environment as hunter/gatherers. But the reality is that humans are highly adaptable and, in general, evolution favors behaviors that allow us to survive and bear young. We don’t have to be perfect to have children, and evolution does not have an end goal. It’s not surprising that people will go to great lengths to rationalize what they are eating and how they are living, because in the end we mostly just want to be happy and healthy. But the assumptions that diet adherents make about the paleo lifestyle are just not accurate, as Zuk points out throughout the book.
Even without these compromises from natural selection acting on our current selves, we have trade-offs and “good enough” solutions that linger from our evolutionary history. Humans are built on a vertebrate plan that carries with it oddities that make sense if you are a fish, but not a terrestrial biped. The paleontologist Neil Shubin points out that our inner fish constrains the human body’s performance and health because adaptations that arose in one environment bedevil us in another. Hiccups, hernias, and hemorrhoids are all caused by an imperfect transfer of anatomical technology from our fish ancestors. These problems haven’t disappeared for a number of reasons: just by chance, no genetic variants have been born that lacked the detrimental traits, or, more likely, altering one’s esophagus to prevent hiccups would entail unacceptable changes in another part of the anatomy. If something works well enough for the moment, at least long enough for its bearer to reproduce, that’s enough for evolution.
(Emphasis mine.) On a related note, if you enjoyed this book, you would also enjoy Your Inner Fish by Neil Shubin, referenced heavily in the above paragraph.
If you know a few people who are attempting the paleo diet (which is, by the way, the least recommended diet plan ever), you may have noticed that some of the rules seem arbitrary or contradictory. As an example, here is a recipe for “Paleo Avocado Fries” that uses almond flour and baked avocado. Technically, the fries adhere to the paleo diet rules, but did our ancestors really use ground almonds as a crunchy breading? Also, wild avocados look much different than the ones you can buy in the store–they have a bigger nut to flesh ratio (porn reference unintended).
There is a decent summary of the paleo diet rules here, but in short, you can’t drink milk or eat grains but you can eat a ton of meat. People who stay with the paleo diet claim that they are healthier, but we could all be healthier by cutting out processed foods. However, cutting out milk and grains? There is plenty of evidence that early humans who domesticated animals also drank their milk, and evolution favored those who had lactase persistence and were able to digest it (because it is an excellent source of nutrition and hydration). I’m going to make an assumption here that people who practice “being paleo” don’t actually make their own clothes from animal skins, hunt or gather the majority of their own food, or give away their cars.
The book also talks about subjects like:
- Examples of evolution happening before our eyes, in humans and animals (I really enjoyed this section)
- Paleo life and exercise (the “barefoot” shoes are mentioned)
- How monogamy and polygyny fit into evolution
- Differences in perceived sex roles (spoiler alert: women did not just stay at home and tend to the kinds)
The book doesn’t set out to refute the claims about the paleo lifestyle, but rather to provide some context on the reality of the situation. Not everything with the word “paleo” attached is bullshit. In fact, there is a section about parenting that discusses why we (in the Western world) feel like we need to separate babies and parents at night.
We can trace the history of the Western concern that infants sleep alone back to a complex mixture of Freudian thought, concern about medieval mothers deliberately smothering their children, and other kinds of parental advice. McKenna and his colleagues examined the widespread belief that cosleeping–having an infant either in the same bed as the parent or in a bassinet or other device attached to the parental bed–is linked to SIDS, and found no support for the notion.
The author stresses later that however you parent your children, they will likely turn out just as fine as everyone else.
None of the researchers imply that Western parents are bad parents, that non-Western children live in an idyllic manner we should all emulate (for one thing, there is no single “non-Western society”), or that all babies that cry for longer than a minute are irrevocably scarred for life or have something wrong with them. All of the researchers stress the plasticity of human behavior, and the inevitable variation among infants and their parents that makes general proscriptions for child care risky. But babies do seem to have evolved in an atmosphere of immediate and frequent tending by multiple individuals, which suggests that large deviations from that environment may be hard on modern infants.
By the way, if you haven’t heard of the work of Harry Harlow (“best known for his maternal-separation, dependency needs, and social isolation experiments on rhesus monkeys”), look him up. If you have heard the sad story of the wire-mother versus the towel-mother, you will know what I’m talking about.
My only complaint about this book is that the author uses internet comments as example of what paleo adherents believe. They may be representative of some people, but we all know it’s not too hard to find people who are wrong on the internet. Responding to internet comments gave the book a more vindictive better-than-them vibe which was completely unnecessary (even though I’m sure the author did not intend it to be like that).
I’m going to end this book summary by saying that ultimately, people may live their lives however they choose to and it doesn’t bother me one bit. You want to pretend you’re a modern-day caveperson? Fine! You want to wear those freaky shoes with the toes? OK! You enjoy your meat grass-fed, organic, locally-raised, cruelty-free? Me too! But don’t say something is “science” when you don’t have a good understanding of the facts.
Also, this month I did not come up with a themed recipe, but instead I brought a bunch of snacks from my NatureBox because they’re healthy and blah blah (actually I was trying to offload some excess almonds that I received because I don’t like eating whole almonds). Note: I did not receive a sample or anything for mentioning NatureBox, but it is a pretty neat service if you are trying to eat healthier snacks.
Next Month: The Great Agnostic
We are reading The Great Agnostic: Robert Ingersoll and American Freethought by Susan Jacoby and I will be putting up a post on Sunday, August 25th. If you’re going to be in Boston on the 24th, consider coming to our in-person meeting! Add a comment here if you need more information about that. See you next time!