A Cerebral Thanksgiving: Cooked Food and the Human Brain
November 26, 2012
As the last slices of leftover turkey are made into sandwiches, and the final pieces of pumpkin pie disappear tragically from the fridge, the Thanksgiving season has brought us another lovely celebration of family, fall, and food. But how frequently do we think about why we eat our food cooked? Most animals would dive into a raw turkey without ever worrying about pre-heating the oven to 325 degrees, or debating whether stuffing might cause the bird to cook unevenly.
Scientists at the Federal University of Rio de Janeiro now suggest that early humans’ propensity to cook their food may have been chiefly responsible for the development of their larger brains, as compared to their primate counterparts.
Cooking, in its most basic, non-artistic form, begins the process of digesting the food we eat. It takes less energy to break down turkey that has been in the oven all afternoon than it does to break down raw turkey fresh from the farm, or suburban supermarket.
While humans are capable of metabolizing 100 percent of the nutrients available in cooked food, they can tap only an estimated 30 or 40 percent of those in raw food.
The researchers in Brazil, who conducted an extensive study on the brain sizes and eating habits of a variety of primates, propose that by learning to cook their meals, early humans could spend less energy in digestion, and less time in hunting and foraging. This economization of time and energy, as essential to early Homo erectus as it is to high school students today, allowed our ancestors more time to socialize, to innovate, and ultimately to stimulate their brains.
How early humans began to cook in the first place remains unclear, with an accidental discovery by dropping raw meat on the open fire lasting as a popular hypothesis.
The researchers calculated that, were we to eat our food raw, humans would need to spend nearly nine and half hours a day eating in order to maintain our current brain mass.
It would then be very challenging to endure Mr. Roisen’s strict no-food policy, especially on block days, as an hour and a half of precious eating time would be lost in the pursuit of biological knowledge.
Orangutans, gorillas, and other primates that have significantly smaller brains per body mass than do humans, spend much more of their waking lives foraging for and consuming food. Orangutans spend around 7.8 hours a day either searching or shoveling. Gorillas spend an astounding average of 8.8 hours in the pursuit of nutrients each day.
While Thanksgiving Day may have seemed to present a nation of humans who do spend eight or nine hours either consuming or recovering from food, had humans not learned to cook, there would have been little time to spare for midnight Black Friday specials.
And that would really be a shame.