The simple, everyday act of cooking could have given humans an evolutionary edge over apes, researchers proposed at a scientific meeting this week.
Preparing meals is a "signature feature" of the human diet that likely originated in the extinct species Homo erectus 1.8 million years ago.
"The hallmark of dietary evolution is our flexibility and plasticity. What made humans humans is the ability to find or make a meal in the environment," said William Leonard, an anthropologist at Northwestern University who was not involved in the new research.
H. erectus had a large brain and body size, and many believe that the species' hunter-gatherer lifestyle—associated with more cooked meat—fueled its growth.
But scientists aren't sure why these first chefs initially put food to fire.
Yesterday Richard Wrangham, a biological anthropologist at Harvard University, served up new evidence for his hypothesis: Cooking decreases the energy cost of eating.
For primates, including humans, "energy is absolutely critical, and [it's] what natural selection is constantly trying to maximize," Wrangham said during a preview of his work at the American Association for the Advancement of Science's annual meeting in Chicago.
Cooking makes starchy things gelatinous, breaks up proteins, and softens rock-hard edibles, Wrangham said. Such textural and chemical changes make foods easier to eat and digest.
Designed for Cooking
The shift to cooking is reflected in modern human anatomy. For one, our jaws are considerably smaller—and thus less able to bite into hard foods—than those of our earliest ancestors.
Also, our gut is not set up for processing raw items as effectively as cooked food.
What set us apart from apes, Northwestern's Leonard said, was a need for a high-quality, high-calorie diet, combined with a drive to be active over a large area.
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