Adherents of the so-called “Paleo diet,” which emphasizes meat and attempts to replicate what humans ate in the Paleolithic period, may want to set down their steaks long enough to say thanks for starchy carbs. An international team of researchers, writing in The Quarterly Review of Biology, makes the case that plant foods – not just meat eating and the discovery of fire for cooking – were essential to the development of the human brain. Together with the evolution of enzymes in saliva that help predigest starches, they argue, “digestible carbohydrates were also necessary to accommodate the increased metabolic demands of a growing brain.”
The human brain, the scientists point out, uses up to 60% of the body’s blood glucose. Pregnancy and lactation place additional demands on blood glucose. “Cooked starch, a source of readily available glucose, greatly increased energy availability to human tissues with high glucose demands, such as the brain, red blood cells and the developing fetus.”
Of course, our ancestors didn’t have access to modern supermarkets, where starchy foods are available in overabundance. Today, experts say, most people need to avoid refined starches along with sugars.
For more on the Paleo diet, see our July Special Report, “Should You Eat Like a Caveman?”