Catching Fire: How Cooking Made Us Human

catching fire

There are many things that separate humans from the rest of the animal kingdom. Our language, expression through art, contemplation of the universe beyond us, and heating, mixing, and flavoring our foods before we eat them. Did all of these advancements develop simultaneously as we evolved? Or did one lead into all the others? In Catching Fire: How Cooking Made Us Human by Richard Wrangham, he connects the point when humans harnessed fire and started cooking regularly with the point where we started evolving into the large brained, small jawed, small gutted, hairless creatures that we are today.

I was led to Wrangham’s book because Michael Pollan references it multiple times in Cooked: A Natural History of Transformation, and subsequent articles about the book (which will get a post of its own after a rereading).  Wrangham lays out expansive evidence that the whole reason our bodies have evolved to what we are today (and the additional developments that arose from our larger brains) came from the simple concept of adding heat to food.

“Cooked food does many familiar things. It makes our food safer, creates rich and delicious tastes, and reduces spoilage. Heating can allow us to open, cut, or mash tough foods. But none of these advantages is as important as a little-appreciated aspect: cooking increases the amount of energy our bodies obtain from our food” (14). Being able to more easily obtain energy from food had many advantages. Besides the fact that it tastes better most of the time, cooked food is far easier to eat (and in some cases makes otherwise inedible things edible, like the potato). Plus we spend about four less hours per day chewing cooked food (142), and then we extract far more energy from the food consumed. Four more hours a day where we no longer have to sit idly and chomp is the equivalent of sixty days a year (!!!) that we get back and can use towards all sorts of productive endeavors.

Studies today have compared cooked and non-cooked diets, and come back with ample evidence for the evolutionary benefits of cooked food. Those who were eating a cooked diet, whether there was meat included or not, did not show a difference in body weight. The more raw food consumed, the lower the person’s BMI and for women an increased likelihood that they partially or entirely stopped menstruating (20). This decreased the likelihood of conception, so women with a cooked diet who menstruated regularly would have a much better chance of conceiving and passing on their smaller guts and cooking knowledge.

Consuming solely raw food now is either an extreme necessity or fanaticism (and the fanatics are likely to be very well off) (38). When not done to the extreme, raw food consumption can be an effective weight loss strategy. Digestion is an energy intensive process though (as much as moving around), so not having to do as much of it and limited the space it is done in with a smaller gut are the evolutionary advantage (40). Heat denatures proteins, which makes them easier to digest because the complicated structures are open to digestive enzymes (65).

The idea that cooked food was the catalyst to our current body shape and the society that we know today is fascinating but not surprising. Cooking is a universal activity, done no matter what the local ingredients are. No cultures rely on raw diets (54), we all cook before eating. I’ve always loved cooking as a universal phenomenon, and besides being a cultural connection it is the evolutionary evidence that explains our physique. It is interesting that though cooking food provided an energy boost and positive evolutionary changes, the advent of agriculture led to the first widespread scarcity and malnutrition (as I discussed in the post about Sex at Dawn). Migrating, foraging,  and cooking food did not have any adverse affects, but staying in one place and trying to grow and eat the same cooked food did.  Some may see cooking as just one of the many activities that sets our species apart, but it was a monumental development that shaped our bodies and gave us the time and energy to pursue more than just survival activities and build a complex society.

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Sex at Dawn

sex at dawnOne of my goals for this space is to write about food-related books, so it is only appropriate that I start with one about sexuality! Sex at Dawn: The Prehistoric Origins of Modern Sexuality by Christopher Ryan and Cacilda Jethá explores the fairly recent development of monogamous relationships as the norm in many societies.  Our anatomy, what we know about prehistoric societies, and comparison to our closest animal relatives (primarily bonobos) suggests that for most of human existence we lived in equitable groups that shared everything, including food, child care, and sexual partners.

I picked up the book intrigued by this premise alone, but really got into it when Ryan and Jethá started discussing when the transition from egalitarian groups to property owning individuals happened: the onset of agriculture. This shift caused many changes in the set-up of society. Hunters and gathers stopped doing so much of those defining activities, and spent far more time in one spot. Individualism, owning property, monogamous relationships and having more offspring to work on the farm became main priorities.

I assumed that this shift would have accompanied more continuous prosperity and reliable food sources, but skeletal evidence proves the opposite: that our ancestors did not experience widespread scarcity until they settled in agricultural societies (181). The health changes caused by shifting from foraging to farming around 1200 AD were not positive: “Archaeologist George Armelagos and his colleagues reported that the farmers’ remains show a 50 percent increase in chronic malnutrition, and three times the incidence of infectious diseases (including bone lesions)….increased infant mortality, delayed skeletal growth in adults, and a fourfold increase in porotic hyperostosis, indicating iron-deficiency in more than half the population”( 173-4). This outcome is very similar to the nutrition transition that occurs when people move from traditional to western style diets highly concentrated in sugar, fat, and animal products, which increases obesity and the many diseases that accompany it.

There was no need for people to stay rooted to a spot that was not producing enough food before farming. Being constantly on the move also made close, successive pregnancies very unlikely so there were rarely more mouths than could be fed. This kept the population small and mobile in a world with abundant food (160). Because there was very little property and all things were shared, there was no such thing as poverty. There was also very little abuse of resources, because in a small society it is very easy to keep people accountable. But once the population size grew so big that individuals could not easily keep track of one another (Dunbar’s number), there began an inevitable abuse of resources (170-1).

In Sex at Dawn Ryan and Jethá quote Marshall Sahlins from his book Stone Age Economics: “Poverty is not a certain small amount of goods, nor is it just a relation between means and ends; above all it is a relationship between people. Poverty is a social status. As such it is the invention of civilization.” The shift to an agricultural society caused more disease, scarcity and the creation of poverty. We have also far surpassed the point where reverting back to a nomadic lifestyle would be a solution to our current widespread health, resource, and other issues.  Obviously our current population could never be supported by hunting and gathering, nor would most people want to live that way. So the question now is: how can we live in a capitalist agrarian society and be healthy, happy people? Can we live in large populations without poverty, and without reverting to an extreme vegan communist society?

PS – He doesn’t mention the agricultural aspects, but Ryan did give a TED talk that gives a good overview of the rest of the book.