About 6 million years ago, our ancestors had experienced a tremendous brain growth, widely viewed as a “major adaptive shift” in human evolution. Half of human brain composition is fat and 20% of its dry weight is long‐chain polyunsaturated fatty acids (LCPUFA). Consequently, improvements in consumption of dietary fat were necessary condition for promoting encephalization. Dietary fat quantity and quality have been subjected to tremendous change over the past 10,000 years with the introduction of industrially produced trans fatty acids and reduced intakes of ω‐3 fatty acids. The absolute human brain size reached its peak of approximately 90,000 years ago and has decreased by 11% since 35,000 years ago, most of it (8%) coming in the last 10,000 years. The shortfall in consumption of animal foods since the late Paleolithic and mainly consequent shortfall in consumption of preformed LCPUFA would be the plausible hypothesis for the brain size decreasing. Genetically, we are still adapted to the East African ecosystem on which our genome evolved, with some adaptations since the Out‐of‐Africa Diaspora. Dietary fat quantity and quality change has caused a conflict with our slowly adapting genome and this mismatch is likely to be at the basis of “typically Western” diseases. Many recommendations for the intakes of EPA + DHA have been issued, notably for prevention. However, the ultimate goal might be to return to the fat quality of our ancient diet on which our genes have evolved during the past million years of evolution.
Part of the book: Superfood and Functional Food