Describe your latest book.
Why do we cook? Traditionally we see cooked food as a pleasant luxury without any particular significance for human evolution. We like hot meals for their smells and tastes and textures and for helping protect us from disease. Yet, depending on our personal preference, we can eat our food either cooked or raw, be it apples, carrots, or even beef.
Catching Fire: How Cooking Made Us Human says conventional wisdom is wrong. Cooked food is a necessity in almost every human lifestyle. All societies cook their food. The only people who live without eating any of their food cooked are "raw-foodists," members of rich societies who for health-related or philosophical reasons have committed themselves to a restricted diet. The diets of raw-foodists come from domesticated animals and plants (especially fruits and nuts) that have markedly higher nutritional quality than wild foods. Yet despite eating foods of exceptional quality compared to anything one can find in the wild, raw-foodists tend to suffer such a deficiency of energy that in addition to being thin, most raw-foodist women are infertile. Such evidence shows that humans are biologically adapted to cooked food.
The realization provokes fascinating questions about the causes and effects of our unique diet. Why can humans not digest raw food as well as other animals do? Why is cooked food so valuable? When and how did our commitment to cooked food arise? How has our reliance on eating by the hearth affected human behavior and society? What significance does cooked food have for our health?
Catching Fire reports that our ancestors were able to abandon their ability to digest low-quality raw foods because cooking provides much more energy than raw food. Our adaptation to the new technology is signaled almost two million years ago in the emergence of Homo erectus, the first in our lineage to have the small teeth and small guts that characterize humans. Cooking also changed our societies. It softened our food so much that it saved us from hours of chewing every day, allowing us a new focus on hunting. Women became the preparers of domestic meals, so with cooking came households, the basis of the human family. Cooked food allows our babies to be weaned early, our births to be frequent, and our brains to be large.
When I talk about Catching Fire, I find a common response is puzzlement that although the ideas seem right, they are new. How come, I am asked, no one has suggested before that cooking explains much about who we are? A large part of the answer is that the question of when our ancestors first controlled fire has been discussed mostly by archaeologists rather than biologists. Many archaeologists have insisted that fire could not have been controlled until the time when it is comparatively easy to find traces of fire, such as a quarter of a million years ago. That argument carries with it the implication that cooking has been biologically unimportant, since at the relatively recent times that archaeologists can find a lot of evidence for control of fire, little happened in the evolution of human anatomy. Some archaeologists have therefore reacted to Catching Fire by claiming that fire cannot have been controlled as early as I suggest. They need to remember that traces of fire tend to decay so quickly that even if an ancient site has no charcoal or other hints of burning, we cannot conclude that fires were absent.
Perhaps even more important, the role of cooking in making more energy available has never been demonstrated until now. I started thinking about how cooking gives us calories when studying the feeding behavior of wild chimpanzees. Sometimes I would spend all day without bringing any food of my own. I would try eating the same wild foods as the apes, but I rapidly learned that it is impossible to satisfy one's hunger in the forest. The fruits that chimpanzees eat are mostly fibrous, nasty tasting, and hard to chew without swallowing indigestible pieces of skin or seed. Even the meats are unattractive, tough, and low in fat. These foods left me hungry and enormously appreciative of a big bowl of steaming pasta back in camp at night. Yet as I did the research for Catching Fire, I learned that there is much confusion within nutritional science about the importance of cooking for the energy value of food, or even how to measure it. Even now some nutritionists have objected to the energy theory of cooking, noting that the number of measured calories in a piece of food is the same whether raw or cooked. What they forget is that cooking both increases the proportion of the nutrients that are digested, and reduces the amount of energy that the body expends in the course of digestion. It will take much research for the energy effects of cooking to be precisely quantified, but as I report in Catching Fire the effects of both increased digestibility and reduced costs of digestion are very large, to judge from the few direct experiments that have been performed to date.
My own strongest reaction from researching Catching Fire has been astonishment at the gaps in our knowledge. Cooking is the signature feature of the human diet, and in such phrases as "you are what you eat," we have long recognized the importance of food. So I remain amazed that, until now, the nutritional significance of cooking for the acquisition of energy has barely been investigated; the biophysics of food has been given hardly any attention compared to its biochemistry; the digestive adaptations of Homo erectus have not been explained; the dependence of men on women cooking for them has been little discussed; and the role of extra energy in accounting for the unique biology of humans has been examined very little.
Freed from the constraints of an excessively confident archaeology, and of a nutritional science that ignores the vital role that cooking plays in giving us calories, we have new opportunities to explore where humans come from and who we are. The adventure of understanding our relationship to fire has only just begun.
What's the strangest or most interesting job you've ever had?
When I was 18 I assisted a biologist in Zambia to immoblize elephants. The task involved a team of four approaching wild unhabituated elephants as close as possible on foot without being detected. John Hanks, the biologist, fired a dart from a crossbow, then we followed the elephant until it stood still. Hoping the elephant was then asleep, John very bravely went slowly up and pulled the elephant's tail to make sure it was asleep. We then had to get the elephant on its side. All four of us pushed on it, on legs and belly. The elephant would not fall easily. Typically we heaved enough to start it leaning away, then it would swing back in our direction at alarming speed. We had to run rapidly backwards, only to rush forward and push again as it swayed away from us once more. None of us ever got trapped under the elephant's falling body but it sometimes seemed a near thing. We drew huge numbers with indelible paint on the elephant's back, and later read them from small planes. We found that the elephants were traveling vast distances, even leaving the country.
Offer a favorite sentence or passage from another writer.
Of all the books produced since the remote ages by human talents and industry those only that treat of cooking are, from a moral point of view, above suspicion. The intention of every other piece of prose may be discussed and even mistrusted, but the purpose of a cookery book is one and unmistakable. Its object can conceivably be no other than to increase the happiness of mankind.
—Joseph Conrad (1923), foreword for his wife's cookbook, A Handbook of Cookery for a Small House
How do you relax?
When Gibbon was writing The Decline and Fall of the Roman Empire, he was said to compose each paragraph while walking outside in the garden, then return and write it down as a whole. The exercise led to a satisfyingly complete rehearsal of his idea. I have no such high ambitions but I do find that country walks in which I set myself the challenge of solving a problem or understanding an idea allow a wonderful escape from the distractions of a working office. I am enchanted by birds and trees, and I return refreshed whether or not I succeeded in the task I set myself.
How did the last good book you read end up in your hands and why did you read it?
A friend recommended Chimamanda Adichie's Half of a Yellow Sun very strongly and thrust it into my hand. I liked the idea of a war novel written by a woman, and as someone who spends a lot of time in East Africa I was interested to learn about Nigeria. Adichie brings the Biafra War alive simply by describing how an educated family declines into poverty and suffering. The military action is undescribed, a distant backdrop to the small events that build into personal tragedies. I was swept up by a moving story that gave dignity to the weak and powerless.
Describe the best breakfast of your life.
They happened every Saturday during term-time from the age of 8 to 12. I was in a small private school, and the breakfasts were mostly awful, especially the warm herrings mid-week. But on Saturdays, we had scrambled eggs (powdered eggs, mind you) and deep-fried white bread. They were probably full of bad things such as saturated fats, but all week I looked forward to this rich, greasy meal, and was never disappointed.
Why do you write?
In my professional life I write for scientific journals. Writing science for non-scientists is in many ways harder, but it has special rewards.
Who are your favorite characters in history? Have any of them influenced your writing?
The trouble with most historical characters is that they were powerful men, and as Lord Acton said, "Power corrupts, and absolute power corrupts absolutely. Great men are almost always bad men." So my favorite historical characters are thinkers. Charles Darwin is my ultimate hero not just because he is responsible for the most important idea of all time, but also because throughout his life he strove for honesty and fairness. He delayed for decades from publishing about evolutionary theory, apparently because he wanted to totally understand the ideas before committing them to his readers. In the end he was forced to be more realistic to avoid being scooped, but by the time that he wrote The Origin of Species he had already examined his arguments from so many different angles that they were thoroughly convincing. He was also a very moral man who worried about the effects of his ideas on the happiness and behavior of others. He is close to an ideal model.
Dogs, cats, budgies, or turtles?
Dogs. They are intelligent, giving and demanding creatures who remind us daily of the importance of social relationships. They teach us to care: young couples should all have dogs before they have children. Our yellow Labrador, Barra, thinks with his stomach and would be as friendly to a burglar as he is to us, but we can forgive him anything because his wagging tail and nuzzling head so readily brush away a day's worries.
Recommend five or more books on a single subject of personal interest or expertise.
Five Great Books about Foreign Cultures
From the Holy Mountain by William Dalrymple
The disappearing of Christianity from its homeland in the Middle East.
Great Hedge of India by Roy Moxham
Detective story about a vanished tax system.
The Classical World by Robin Lane Fox
Greece and Rome in fresh eyes.
Come on Shore and We Will Kill and Eat You All by Christina Thompson
The relationship between Britain and New Zealand, and Europeans and Maoris, told by a rich American who married a poor Maori.
The White Nile by Alan Moorehead
Tales of derring-do in 19th-century colonial Africa.