31) Survival of the fattest: fat babies were the key to evolution of the large human brain

Cunnane SC et al; Comp Biochem Physiol A Mol Integr Physiol. 2003 Sep; 136(1):17-26

Membranes of cells that have lots of electrical activity (photoreceptor, brain, heart) have higher proportions of the specialized polyunsaturated fatty acid, docosahexaenoic acid (DHA).

Body fat therefore contains two types of insurance— fatty acids to make ketones for brain fuel and lipid synthesis, and specialized fatty acids such as DHA for brain membranes

On a per weight basis, body fat contains more DHA at birth than at any other time in the lifecycle. Infants with normal amounts of body fat at birth have a supply of DHA in their fat that would meet the brain’s requirement for approximately the first 3 months of life irrespective of what was in the milk or mother’s diet.

DHA insurance bestowed on human infants born at term.