If a raw food diet appeals to you, think twice. New research from Brazil suggests that the capacities of human brains evolved far beyond those of gorillas and chimps because our early ancestors learned to cook food. Investigators at the Federal University of Rio de Janeiro determined that human brains have an average of 86 billion neurons, while gorillas have 33 billion of these brain cells and chimps only 28 billion. They also found that the more neurons a brain has, the more calories are needed to support its function. If humans ate only raw foods, the researchers calculated, we would have to eat for more than nine hours straight in order to get enough calories to sustain the energy requirements of our bigger brains. The investigators also report that the human brain consumes 20 percent of body energy when resting compared to nine percent in other primates. Researchers elsewhere have suggested that human brains began to expand once our ancient ancestors learned how to cook food over fire. And lab studies have shown that animals grow up bigger and faster when they eat cooked, rather than raw meat. The study from Brazil was published online on October 29, 2012 in the Proceedings of the National Academy of Sciences.
My take? These are interesting evolutionary findings, and I find them quite sensible. The main argument in favor of eating this way is that cooking destroys vital enzymes in foods. In fact, these enzymes play no role in human nutrition, because stomach acid destroys them as efficiently as cooking. In addition, some nutrients found in vegetables are actually less bioavailable when you eat these foods raw. Another disadvantage of eating foods raw is that many of the natural toxins in edible roots, seeds, stems and leaves can be destroyed by cooking them in water.