Diet and human evolution go hand in hand, especially the evolution of the human brain and its internal wiring. Having hands, with four fingers and an opposing thumb, a bipedal upright gait, an a foramen magnum located at the center of the base of the head favored greatly the evolution of the human brain. However, it would never have happened without the right kind of food to boost it. And in terms of cerebral cortex evolution, the right food simply means the right fuel, the kind of stuff that provides you with enough calories for a demanding organ such as the brain, which uses up to 27% of the total fuel you have in your body in the form of glucose, ketone bodies, and fatty acids. But the question is what was the richest source of calories hundreds of thousands of years ago? At a time when there was no agricultural products and, therefore, carbohydrates, such as starches (flour) and sucrose (table sugar)?
Thousands of years ago, as it is today, it is saturated fat, animal fat, the food that contains the greatest amount of calories; 1 gram of carbohydrate contains only 4 calories, while 1 gram of fat has 9 calories. But where did primitive man find saturated fat? He found it in the skulls and long bones of animals in the form of brains and marrow. Yes, at the very beginning man was a scavenger that ate a lot of bone marrow and brains. Many years later, when he became an accomplished and skillful hunter, he would also find saturated fat in animal livers, entrails, and meat. Not only does fat contain more calories than carbs, but it also gives you, when you do not eat carbs at all, a different metabolic state called ketosis. And this different metabolic state was the key to the evolution of the human brain since it promotes the generation of new nerve cells.
Early hunter diet and brain bundles development
The diet of primitive man consisted of 60% fat, 30% meat, and 10% vegetable fibers, almost the kind of diet Siberian tribes and Inuit people eat. And it is called ketogenic diet, which put you on ketosis, which means that most of your body cells uses ketone bodies, which are a lot more efficient fuel than glucose (sugar).
One molecule of the fat a primitive hunter ate was downgraded in his duodenum by an enzyme called lipase into three smaller molecules: two fatty acids and one molecule of glycerol. These three smaller molecules traveled in his bloodstream through the superior mesenteric vein and portal system into his liver, where they were further downgraded by the hepatocyte mitochondria. Fatty acids were broken down into three types of ketone bodies (beta-hydroxybutyrate, aceto-acetate, and acetone).
Ketone bodies were used by his muscle fibers and brain neurons as fuel to produce ATP instead of glucose. Since beta-hydroxybutyrate leaves no free radicals as glucose does, this ketone body promoted in the primitive hunter brain neurons the neogenesis of new mitochondria, which produced more ATP per minute, accelerating his metabolism. And this reproduction of new mitochondria boosted in turn the neuroneogenesis of the nerve cells, which is the production of new neurons. And the more neurons he had in his cerebral cortex, the thicker his brain fasciculi (bundles) became.
Your food choices have a profound influence on your brain function and health. Fatty acids and ketone bodies stimulate the production of new mitochondria, triggering the division of neurons (video)