Paleofantasy

What Evolution Really Tells Us About Sex, Diet and How We Live

by Marlene Zuk

Published Feb. 2013 by W.W.Norton & Co., 328 pages

When I was in high school, first learning about genetics, things seemed fairly simple and straightforward.  Blue eyes, a recessive trait, required two genes, one from each parent, specifying blue eyes.  Otherwise, the eyes would be brown, being from a dominant gene.  Since then, with the explosion of scientific knowledge of molecular biology and the analysis of the entire human genome, the world of genetics and evolution has, well, evolved, to put it in the phrasing of Dr. Zuk, a professor of Ecology, Evolution and Behavior at the University of Minnesota.  But it is as if we have just dipped our toe in a vast and unexplored ocean, which was previously unknown.

I picked up this book at my favorite book shop in the U.S., Northshire Bookstore in Manchester, Vermont, while on a ski trip in February.  The title captured my interest.  There is a huge “Paleo” movement at present, based on the theory that our genes adapted to life of the paleolithic time, that is, from about 2.5 million years ago to about 10,000 years ago.  This covers a lot of time, from when earliest human-like creatures developed, to the development of modern homo sapiens.  A search on Amazon for books with paleo in the title yields 2,719 titles, very few of which have to do with actual paleontology.  They are almost all about eating paleo, living the paleo lifestyle, and there was even a paleo cookbook for your dog.  The concept is that humans evolved before the era of agriculture, caught their meals in bursts of speed chasing down animals, gathered vegetable food from nature, and walked and ran barefoot.  Thus, the argument goes, we are best suited for this type of food, and life, and that our genes are ill equipped to handle crops such as grains, non-meat sources of protein, and running long distances, especially in shoes.  There are also devotes to various concepts of how stone-agers lived in family units, or groups, how they coupled up and reproduced, and whether there was pairing for life versus multiple partner life.  The purpose of devoting oneself to a paleo lifestyle, then, is to be in harmony with ones nature and genes, to be healthier, leaner, fitter, sexier, have less immunological problems, and presumably, to be able to run injury free.

Dr. Zuk starts off with a brief description of human evolution.  She explains some of the complexity of the evolutionary process, that many human ancestor lineages were changing in different ways, that we share an enormous percent of our genome with earlier species right down to bacteria, and that evolutionary change is not always change for the good.  She points out some of the complexity of genes being favorable or unfavorable for survival.  For example, if a trait is unfavorable, and results in loss of that trait, other genes will be lost along with that  trait due to their being linked together.  She gives specific examples. She also documents that there was not just one paleolithic lifestyle; there were many different routes taken along very different paths.

Her second major point is that evolutionary change can happen quickly or slowly, and may occur without any type of survival pressure.  An argument of the paleo adherents is that our genes were fixed back in pre-modern times, and that the last 10,000 years is too short a time to allow for adaption to new foods, and new ways of living.  She rebuts this with specific examples of changes that have occurred in that relatively short period.  Blue eyes, mentioned above, came about in the last 10,000 years.  Lactose intolerance seems to have a lot to do with where and how one’s group survived, and is also very recent.  It has the complex nature of being caused by a lack of a gene to inhibit built in turning off of another gene which inhibits lactase production as one matures, lactase being the enzyme required to digest lactose.  She mainly discusses genetic changes which are changes in gene expression, as opposed to major gene alterations such as occur with mutations.  In other words, she’s not talking about how we got to be human, but rather how our genome is modified over time to adapt to our surroundings.

The following chapters deal with diet, food procuring methods, exercise or physical activity including running, sex, monogamy versus multiple partners, family structure, child raising, susceptibility to diseases, and how we protect ourselves from disease.  Her discussions of these topics are backed up with scientific studies, and she cites the literature from which she makes her arguments.  She also points out where the science does not support the claims made by paleo adherents, thus the “Paleofantasy” of the title.  In many ways, she does not try to say that the “paleo” approach to diet or exercise is harmful, just that it is not based on real scientific reasoning.  As with any devoted scientist, she includes a lengthy bibliography which she used to form her arguments, as well as a notes section and an index.

Her writing style was an interesting, and sometimes to me, annoying mix of sound scientific argument with a conversational tone that seemed unnecessary.  It was like watching a really good Nova TV show on a particular topic, and then having a few lines from the sitcom “Cheers” thrown in.  She uses the word “well” a lot, as I used it above in the first paragraph.  I enjoyed the humorous touches, though, and I think she would make a very entertaining teacher in the classroom.  The title of the book is clearly meant to titillate, listing sex as the first major topic, when it’s really primarily about diet.  She got most of her information regarding the paleo lifestyle from the internet and popular books, which makes sense, since it’s not a scientific discipline, but it does make comparisons of real research with what paleo advocates consider perfectly logical thinking a bit one-sided.  This is not meant to be a book for scholars, but for the lay public, and I think she has accomplished that very well without sacrificing the scientific complexity which makes this topic so interesting.

I learned a lot reading this book, about evolution and current thought about genes and molecular biology.  I think she makes very sound arguments that, while living a paleo lifestyle may not hurt you, you won’t necessarily be any better off for it.  She successfully defends her thesis, that the paleo movement is based on fantasy, not fact.  Reading the comments about her book online, there were obviously many adherents of the paleo life who were not only unconvinced by her arguments, but found her book essentially sacrilegious.  In fact, a number of commentators remarked that they would not read the book. For me, it was an exciting look at topics which are themselves changing rapidly as new research is done in the areas of evolution, genes, reproduction, disease, disease prevention, fitness and longevity.  I think anyone who is interested in these topics will find this book fascinating and a good read, as long as you can, well, ignore some of the style issues.

Vlad Averbukh, 29, a follower of the paleo diet, eats raw meat along the Hudson River in New York in 2010.
Emmanuel Dunand/AFP/Getty Images