Professor Wrangham in Tanzania with Hadza hunter-gatherers.

By Laurie Atwater

Sometime between the origin of Homo habiline (2.3 million years ago) and Homo erectus (at least 1.8 million years ago) evolving man learned to cook.

That’s right. At some point, and it’s unclear just when that was, our ancestors learned to control fire and thereafter they began to barbeque.

It’s at that time, when our ancestors harnessed the power of the flame and cooked their meat, posits Richard Wrangham, that we “become human.” Because food was softer and more digestible more energy could be directed to evolution: Bigger brains, smaller rib cages and guts, less prominent jaws and smaller teeth. Precisely because of cooking. So kiss the cook, because without her (and he also thinks it was the female of the

Wrangham’s book Catching Fire will be available for sale at his appearance in Lexington.

species that cooked) we would never have evolved into the amazingly complex creatures that we are.

Wrangham is the Ruth Moore Professor of Biological Anthropology at Harvard University and his research group is now part of the newly established Department of Human Evolutionary Biology. He has made a career of observing and studying chimpanzees in the wilds of Africa. He is the co-director of the Kibale Chimpanzee Project, the long-term study of the Kanyawara chimpanzees in Kibale National Park, Uganda. He has always been fascinated by the effects of the environment and ecology on animals and by extension on humans. Specifically he has been captivated by explaining the evolution of human social systems through the observation of primate behavior.

In his book Catching Fire (Basic Books, 2009) Wrangham presents this theory of evolution and cooking. It has become a controversial and exciting topic in the scientific world. For Wrangham it seems so logical that he can’t believe that it’s “new.”

The traditional line of thinking says that it was simply the transition from a diet of berries and veggies to eating raw meat that allowed the chimp-like australopithecines to evolve into the pre-Homo erectus habilines. Accepting that, what accounts for the huge biological leap between habilines and Homo erectus? Is it the cooking of meat that tipped the balance? Wrangham says cooking allowed humans to get more calories and nutrients from their food spurring the huge biological changes witnessed in Homo erectus. And then there are the sociological changes that arose from cooking—organizing the community around the fireside, the family around feeding of the young and protecting the food and the relegation of women to the “kitchen.”

In Catching Fire Wrangham takes us on a journey that begins with raw foodists and ends with a discussion of the modern diet in this age of plenty. With humor, keen observation and plenty of science along the way, he makes his case. From fascinating factoids about the amount of time early humans would have spent chewing fibrous foods just to get enough nutrition to live, early experiments on a man with a visible colon and discussion of the social norms around food preparation in various parts of the world, Wrangham entertains and educates. This is a book for everyone; it is accessible and fun.

In advance of his appearance in Lexington I was able to chat with Professor Wrangham from his office and his enthusiasm and humor are contagious.

 

Q. Just how did you happen upon this topic and begin to develop your new ideas about human evolution?

A. I was home in my house in Weston and I was thinking about the lecture that I was giving the next day on Homo erectus. The context that I was thinking about it—I was sitting in front of my fireplace with a fire going and the lights out—reminded me of what it was like sitting around a fire in Africa. I started thinking about how long into the past people would have been sitting around fires just like that. Then I started thinking about my experience eating chimpanzee foods and I suddenly realized that there’s no way a human could survive on that diet. Within a half hour I was developing the idea. I wrote it down that night and it had all of the essential elements that I ultimately came to think about.

Q. At the time did you know anything about food and how it changes through cooking?

A. No, that was all intuition! I went into the department [at Harvard] the next day and I was grabbing my students and my peers and saying, ‘all of a sudden it appears to me that cooking should have this huge importance in evolution.’ I was motivated to burrow into the literature and find out what the story was and I was AMAZED to discover that there was no systematic information on the impact of cooking on the energy values that we get from food.

Q. This seems to undermine the idea popularized by the raw foods movement that raw food is nutritionally better for humans than cooked food. According to your theory raw foods would not have yielded enough calories for the huge evolutionary jump between habilines and Homo erectus. You spend a lot of time discussing the benefits of cooking—how it made all food, and meat specifically, safer and more digestible.

A. It seems to me absolutely vital and one really has to get the fact that cooking has huge effects on the food and therefore on our bodies. When I present raw foodies with this evidence they don’t like it. It undermines a philosophy that is quite dear to them!

Q. Most anthropologists accept that meat eating made a difference in evolution, but not meat cooking specifically.

A. I think that people have failed to spot the fact that the raw meat argument doesn’t work very well and I think they have accepted it because they couldn’t think of anything better. Raw meat is incredibly tough and hard to digest. Now, I feel there were two transitions. What has always been accepted, that cooking was not important, is not the case. Whether we are talking about plants or meat, eating cooked food provides more calories than eating the same food raw.

Q. You also contend that cooking became the basis for pair bonding and led to a sexual division of labor—where men protected a particular woman’s food and he gave her meat in exchange for cooking.

A. Once the females are able to provide so much food that a male can rely on her to feed him, the male goes off and hunts. He stops being a gatherer and he can devote more time to hunting. If he has a bad day hunting, he goes off with the rest of the guys in the middle of the camp doing stuff like telling jokes, but he still eats. Overall one has to say women are starting from a disadvantageous position!

Q. Your critics say there is little archeological proof of controlled fire going back far enough to support your claims.

A. We certainly can’t currently make the case on archeological grounds, but something was going on. I imagine that they were pounding away with stones for tens of thousands of years and regularly starting little fires. And that’s where I imagine the young picking it up and playing with it and eventually realizing that other animals are afraid of it. It’s as good a story as any.

Q. And eventually cooking over it?

A. Yes. It’s hard for me to underestimate the control of fire. Once you have an animal that is smart enough to use fire constructively—it’s huge. It’s a fascinating area and if there’s a question of not knowing something, well let’s put it out there so that people will find out what the answer is.

Q. I can’t let you go without thanking you for introducing me to another Atwater—Wilbur Olin Atwater.

A. Ah, yes. The Atwater convention which is still used today, totally misses the impact of food processing on food, but nobody has thought of a way to replace it with anything that is cheap and convenient.

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In the final chapter of his book Professor Wrangham discusses the Atwater convention—a system for measuring calories in food that was developed in the latter part of the 19th century. The USA still uses the Atwater Convention for assessing calories in food despite its known flaws. Highly processed foods require less energy to digest. Yet, the Atwater system is based on calculations that do not take this energy factor into account. The more processed our diet becomes the more net calories we absorb. Obesity is becoming prevalent in cultures where food is plentiful and over-processed.

Once we struggled each day for enough food; now we suffer the consequences of abundance. As a species we are still evolving. What’s next? n