Isn’t it fascinating that the simplest routine of every day life like cooking brought intelligence to our ancestors? Most of us have never even thought about it. Me neither, until I recently had a chance to watch that BBC video “Did Cooking Made Us Human?” Before that I didn’t know much about human evolution except generally known theories like the Charles Darwin “Theory of Evolution” and the facts that our ancestors lived in caves, made fire and got their food from hunting and gathering. Нow could it happen that our predecessors received big brains because they started to cook food? Do scientists have enough evidence to make the conclusions?
The film shows several experiments including observations of raw eaters-volunteers, study of African tribes, feeding tests with mice and snakes, some archeological facts. The evidence was persuasive, but when I read a book of the founder of the theory, Richard Wrangham, Ruth Moore Professor of Biological Anthropology in Harvard’s Faculty of Arts and Sciences, I was convinced even more. In his controversial book, Catching Fire: How Cooking Made us Human, he examines the positive influence of the invention of cooking on human evolution. Wrangham postulates that whenever Homo Ergaster happened to start preparing his food on fire, the human digestive tract shrank and the brain grew. More free time became available for human development.
Nutritionist Carina Koebnick and her colleagues in Germany used questionnaires to study 513 raw foodists who ate 70-100% of their diet raw (Wrangham 17). The research showed that when diet is changing from cooked to raw, significant weight loss, energy deficiency, bad digestion and reduced reproductive function are revealed (Wrangham 17-20). But despite those negative effects, raw food diet is a popular tendency nowadays. Supporters of this practice are assured of health benefits and have philosophical ground for their beliefs. However, our ancestors didn’t have a supermarket across the street, so they couldn’t survive and reproduce without high-energy cooked food (Wrangham 36).
Wrangham asserts when the prehistoric people started to eat cooked food, their bodies began to change gradually (40). Adjusted to cooked food humans acquired “small mouths, weak jaws, small teeth, small stomach, small guts overall” (Wrangham 40). Those small features “fit well with the softness, high caloric density, low fiber content, and high digestibility of cooked food” (Wrangham 44). Due to adaptation to cooked food, we became unprotected from the bacteria that are present in raw meat (Wrangham 53). Moreover, cooked food is many times more energetic than raw food due to the fact that “cooking gelatinizes starch, denatures protein, and softens everything” (Wrangham 57). Experiments on chimpanzees and other animals demonstrated that the more energy we obtain from the food “the greater competitive ability, better survival and longer lives” we have (Wrangham 81).
In 1995 anthropologists Leslie Aiello and Peter Wheeler created a remarkable theory about a dependency between brain and guts sizes. In their article “The Expensive Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution”, the authors pointed out that animals with bigger brains have smaller guts (206). Smaller guts are possible due to eating higher caloric food (Aiello and Wheeler 207). The scientists realized that our brains are especially eager for energy. Although brain takes up only 2.5 percent of human body weight, it needs 20 percent of our energy supply when we are relaxed (Wrangham 109). As archeological artifacts show, two main steps of increasing brain size took place in the development of prehistoric people (Aiello and Wheeler 208). First, it was around two million years ago, from plant-eater Australopithecus to carnivorous Homo erectus (Aiello and Wheeler 208). The second was a little more than half a million years ago when Homo erectus evolved into Homo heidelbergensis who controlled the fire and cooked his meal (Aiello and Wheeler 208). By contrast, Wrenthan shows there were other intermediate stages of the evolutionally increase of brain size (114). They were caused by the use of more advanced techniques to process raw meat by habilines and innovative cooking processes by Homo heidelbergensis and Homo sapiens (Wrenthan 114-127).
The process of cooking also allowed our ancestors to have free time. Instead of chewing tough raw food for hours to obtain enough energy, they now could spend their time on gathering, labor, house keeping and thinking (Wrangham 130). Additionally, the author beliefs “that cooking has made possible one of the most distinctive features of human society: the modern form of sexual division of labor” (130).
Supported by numerous scientific proofs the Wrangham’s logic is convincing, and it’s hard to counter his arguments. French cultural anthropologist and ethnologist Claude Levi-Strauss did not support the biological impact of cooking on human evolution; however, he pointed out that this step from raw to cooked was a manifestation of passage from nature to culture and demonstrates the difference between animals and people. In his influential 1960s book The Raw and the Cooked, where he explores the myths of Brazilian tribes, he writes, “the raw/cooked axis is characteristic of culture; the fresh/decayed one of nature, since cooking brings about the cultural transformation of the raw, just as putrefaction is its natural transformation“(Levi-Strauss 142).
There are a number of human evolution hypotheses. The prevailed one is Man the Hunter. Originators of the theory assumed that the main impact on the human development took place when our ancestors changed their diet from plants to meat. University of Utah biologist Dennis Bramble and Harvard University anthropologist Daniel Lieberman offered another less known hypothesis in which they proposed that running made us human. In their research “Endurance Running and the Evolution of Homo” the scientists argue, “quadrupedal cursors easily sprint faster than humans over short distances, but sustainable ER [endurance running] speeds of humans are surprisingly comparable to specialized mammalian cursors such as dogs and horses…” (Bramble and Lieberman 345). As additional benefit, the human “metabolic cost of transport” is flat over the wide range of speeds (Bramble and Lieberman 346). “Like another group of cursorial bipeds, kangaroos and wallabies, humans are thus able to adjust running speed continuously without change of gait or metabolic penalty over a wide range of speeds”, while horses and dogs have distinct narrow optimal speeds (Bramble and Lieberman 346). The scientists theorize that endurance running caused specific skeletal, thermoregulation and respiration adaptations (Bramble and Lieberman 351). Moreover, “the hypothesis that ER evolved in Homo for scavenging or even hunting therefore suggests that ER may have made possible a diet rich in fats and proteins thought to account for the unique human combination of large bodies, small guts, big brains and small teeth” (Bramble and Lieberman 351).
We love to eat cooked food because it’s tasty, soft and warms up our body and soul. We love to cook, because we are inspired to make the feast pleasurable for ourselves, our loved ones or our friends. We love to be creative when we invent a new dish. We have to cook for our safety. Sitting by the open fire somewhere in the woods, we can imagine finding ourselves in those distant past places where our ancestors for the first time intuitively put their prey on a fire. They became delighted by mouthwatering aroma, heavenly taste, softness and flavor of the meal. They couldn’t resist and continued to roast every meal and the habit made them stronger. Besides, the fire, warmness and good food sure enough were romantic. No doubt it was a great engine!
Aiello, L., Wheeler, P.(1995). The expensive Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution. Current Anthropology, 36(2), 199-221.
Bramble, D., Lieberman, D. (2004). Endurance Running and the Evolution of Homo. Nature, 432(7015), 345-52.
Levi-Strauss, Claude. The Raw and the Cooked. Chicago: University of Chicago Press, 1983. Print.
Wrangham, Richard. Catching Fire: How Cooking Made us Human. New York: Basic Books, 2009. Print.