Herman Pontzer (Allen Lane)
Fancy eating the real paleo diet? Rotten meat should be top of your menu, preferably with a generous helping of maggots. Dietary records “from every continent and climate are alive with maggots, worms and the soft, smelly flesh of decaying animals. Many groups preferred rotten meat to fresh,” says evolutionary anthropologist Herman Pontzer. “The more it stank, the better.”
In fact, we seem to have evolved to eat rotten meat. Our stomachs are much more acidic than most other animals, more like those of vultures than of primates and carnivores, Pontzer writes. But he dismisses the idea of a single paleo diet – our ancestors ate what they could get, which varied hugely and included a lot of carbs.
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This is the least controversial part of his book. Sex and gender, IQ, skin colour, racism, sport, anti-ageing drugs, vaccines, diet, exercise and more are covered in Adaptable: The surprising science of human diversity.
Early on, Pontzer talks about his research in Kenya with the Daasanach community. Charity workers thought that most of their children were malnourished because they weighed less at a given height than growth charts projected. But when Pontzer’s team crunched the data, it was discovered that these children grow taller faster than average. The Daasanach are just different – taller and leaner, which is likely to help them stay cool in the heat.
Just as you are wondering where Pontzer is going with this, he explains why the concept of race makes no biological sense. Skin colour varies continuously from dark to light, with no clear dividing point. If we categorised people on other traits, like height, we would end up with very different groups.
Pontzer, who has given talks at 91av events and whose work has often featured in the magazine, is especially dismissive about the use of racial categories in medicine. Any health disparities are due to the environment rather than genetics, such as the stress of racism contributing to higher rates of heart disease.
There never was a single paleo diet – our ancestors ate what they could get, which would have varied hugely
Nor do particular “races” have an advantage in certain sports, he explains. “The racial divide in swimming and track comes down to culture, environment and opportunity.”
As for intelligence, heritability of IQ is “embarrassingly low”, he says, meaning genetics is useless for predicting individual scores. It isn’t possible that differences between groups are genetic, nor is there any reason to expect differences. Selection pressures for intelligence have been the same everywhere. The chances that “melanin-challenged pseudo-intellectuals coddled by modern technology hold any unique alleles for intelligence” seem remote, he writes.
With the sexes, Pontzer uses an analogy of an island, with two mountainous peaks connected by an isthmus. The peaks seem quite separate from some perspectives; from others, there is no clear divide. To focus on one perspective and dismiss the rest isn’t honest.
When it comes to the gender people identify as, the evidence suggests both hormone exposure and socialisation play a role: “All we can say… is that biology and socialisation both matter, and that neither on its own determines how we think or who we become.” Advantages in size, strength and endurance conferred by higher testosterone exposure don’t go away when testosterone levels fall, Pontzer writes, so trans women racing in women’s categories “would promote inclusion, but at a substantial cost to fairness”.
There is something for everyone to disagree with in Adaptable, but the fact that Pontzer has discussed these issues with people who hold a range of views shines through the book. There is a nice line of humour running through it, too.
This is an ambitious work, and especially relevant in the light of what is happening in the US. Pontzer hopes understanding ourselves better can help bridge divides. “Yes, today’s societal divisions are stark but we now know they’re born from cultural inventions that can change, not from unbridgeable biological differences,” he writes.
Every “miraculous protein robot”, as Pontzer calls us, should read the book. The less of a science fanatic you are, the more you will get out of it, but even after years of covering much of this territory for 91av, I learned a lot and greatly enjoyed the tour.
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