Wednesday, September 4, 2013

Paleofantasy

Paleofantasy: What Evolution Really Says about Sex, Diet, and How We Live
© 2013 Marlene Zuk
328 pages


Despite its name, Paleofantasy is not a deliberate debunking of arguments for a 'paleo diet' and a paleo lifestyle.  Although Zuk does take aim at paleo proponents time and again, her argument approaches the same ideas from a different tack. Rather than assume that people ought to live the lifestyle our bodies evolved to expect, and then look for the science that informs that lifestyle, Zuk first asks:  what does biology tell us about the way our ancestors once lived, and can that information be used to help us today?  Subsequent chapters are a brief survey of the evolutionary heritage of our diet, our sex and childrearing practices, modes of exercise, and health.  The essential point of Paleofantasy is that evolution is an ongoing process: humanity is not a finished product, nor a monolithic species. What is true for some populations doesn't necessarily hold for others.  Thus, studying the lifestyle of our ancestors isn't particularly helpful, because they had different lifestyles depending on their local climate, and each made micro-adaptions in its own way.  Two populations of mountain-living people ,in Tibet and the Andres, both adapted to living in such thin air -- but in two different evolutionary ways. Her message to those interested in paleo living is this: don't get carried away.  By all means, don't overeat and get in a lot of exercise -- but do it because it makes sense now, not because the ancestors starved and were active.

Although the book will probably succeed in cooling the jets of the moderately interested, for more ardent practitioners, she will doubtless fall short, and not just because of defensiveness on readers' part. A staple of paleo nutrition is that grains are of the agricultural devil. Zuk's is response is to point out that look, we've evolved a gene that lets us process starch.  We've adapted! Evolution in action.  She does not, however, address the concern of anti-grain readers that while we can eat grain, we shouldn't because of its insulin-spiking effects and the subsequent relationship with diabetes and obesity.  To borrow an example from her book, also used in Sean Carroll's The Making of the Fittest: while there are snakes who can survive eating poisonous toads,  that doesn't mean they should turn poisonous toads into the bedrock of their snake food-pyramid. Likewise, she doesn't address the rationale that palo-fitness people use in pushing for short, intense workouts, namely that a high level of stress for a short time is better at building bone and muscle than a marginal level of stress done for long intervals.  She simply says "Hey, there are people who have adapted to running really long times."

Paleofantasy doesn't necessarily impress, but it does offer a moderating voice to those who can get carried away by the prospect of living like our ancestors to the point of going to bed with a Sounds of the Nighttime Forest CD playing, because that's what our brains expect.

Related:
Antifragile, Nassim Nicholas Taleb (which includes a section on high-stress short-term exercise)
Wheat Belly, William Davis;  Good Calories Bad Calories, Gary Taubes (on the problems of the modern diet)
Catching Fire: How Cooking Made us Human, Richard Wrangham
Sex on Six Legs, Marlene Zuk.

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