Book Review: Daniel Lieberman’s The Story of the Human Body

In The Story of the Human Body Daniel Lieberman builds a strong case that making fully informed decisions about diet and lifestyle is only possible through the lens of evolutionary history. If you want to know where your body comes from, you need to understand its evolutionary history. Why do humans stand and walk on two legs? Why are we weak compared to other primates of comparable size? Why are our legs and feet shaped the way they are, with springy tendons and arched feet? Why does our spine have a special S-curve? The answer to these questions lies in the the evolutionary history of our species.

Now ask, why do people in modern societies suffer from “diseases of affluence” like obesity, type-2 diabetes, tooth decay, metabolic syndrome, flat feet, nearsightedness, lower back pain, and sleep disorders? Daniel Lieberman argues that these questions can only be fully answered by understanding the evolutionary history of our species. Lieberman argues these diseases are examples of “mismatch diseases” i.e. a disease that is primarily caused by our bodies not being sufficiently adapted to novel gene-environment contexts. We know they’re mismatch diseases primarily because they used to be rare, are largely preventable, and are almost unheard of in hunter-gatherer populations.

Lieberman argues that all of these diseases are in some sense a result of cultural evolution speeding ahead of natural evolution with the result that have humans manufactured a psychologically comfy and satisfying environment that is paradoxically unhealthy without fundamentally affecting our reproductive fitness. Lieberman calls this this paradoxical unhealthiness “dysevolution”. It turns out that surrounding ourselves with unlimited sources of cheap junk food is a bad idea because humans are genetically wired to crave food with dense amounts of fat, sugar, starch, and salt.

Lieberman is no luddite, and certainly doesn’t advocate a return to the caves and giving up on modern science and technology. His position is more nuanced than many of the extreme black and white positions out there, as befitting the complexity of gene-environment interaction. In many senses, the agricultural and industrial revolutions have propelled humans to new heights of health and longevity, with modern science curing diseases and fixing people better than ever before. At the same time, we are living longer but spending many of those years suffering from chronic, preventable diseases. The paradox of the modern world is reduced mortality but greater morbidity i.e. living longer, but spending more of those extra years with an illness of some sort. Lieberman argues that too often the incentives of modern medicine aim at fixing symptoms but not the underlying structural causes: the toxically comfortable environments we built for ourselves.

Book notice: Stephen J. Gould’s The Panda’s Thumb

A used copy of Stephen J. Gould’s book The Panda’s Thumb (1980) has been sitting on my shelf for a while, and I’m kicking myself for not reading it sooner. What a delightful little book of science essays! Each essay is an edited version of one of his monthly columns at Natural History magazine. Subsequently, the essays are intelligible to the general intelligent reader, but Gould does not thereby sacrifice an appreciation for hard facts and subtle reasoning. Gould makes science come alive with his anecdotes, wry humor, and gentle argumentation about topics ranging from the panda’s thumb to hopeful monsters and everything in between. Nothing is too big or small for Gould to think worthy of writing about. All in all, I highly recommend this book for any student of biology or lover of science.

Robert Sapolsky on Major Depression in U.S.

Great lecture; very informative. Sapolsky nicely compresses a lot of research and integrates it into a comprehensive bio-social-psychological model.

The pipedream of genetic astrology

The relationship between genes and visible traits is very different from the way in which it is usually presented to the public. The idea that a gene is a sequence of DNA that codes for a product, and variations in the DNA sequence can cause a difference in the product and hence in the phenotype, is just too simplistic. Coding sequences are only a small part of DNA, and DNA is just a part of the cellular network that determines which products are produced. When and where these products are produced depends on what goes on in other cells and what the environmental conditions are like. Cellular and development networks are so complicated that there is really no chance of predicting what a person will be like merely by looking at their DNA. Although it has considerable rhetorical and marketing power, the dream of genetic astrology is just that – a dream.

~Eva Jablonka and Marion J. Lamb, Evolution in Four Dimensions: Genetic, Epigenetic, Behavioral, and Symbolic Variation in the History of Life, p. 67