The saturated fat that we eat is the most efficient food and form of energy for the human body. It is broken down by lipase (pancreatic enzyme) into glycerol and fatty acids, which is stored in the liver. This organ further breaks down fatty acids into ketones, like aceto-acetate, acetone and beta-hydroxybutyrate during famine or when we follow a ketogenic diet, which is the type of diet the primitive hunter used to have before agriculture, with 60% saturated fat, 30% meat protein, and 10% vegetable and nuts.
The nerve cells and muscle fibers of the prehistoric hunter (Neanderthal Man and Cro-Magnon) used beta-hydroxybutyrate as fuel, since there was not enough glucose level in the blood as there was not carbohydrate foods available. This ketone body is three times more efficient fuel than glucose, promoting the biogenesis of the mitochondria (the cell power plant) and this in turn can induce the neurogenesis of neurons.