”The Ice Age meant that only the fattest animals could survive the cold, providing early humans with access to high-quality animal fats.
These fats are rich in the 20 and 22 carbon fatty acids, which are crucial for brain development and make up 90% of brain material in mammals.
Contrastingly, plants produce predominantly 18 carbon fatty acids, which do not support the synthesis of these essential brain materials. This stark difference in available nutrients presents a clear explanation for the unprecedented growth in brain size during this period. Our brains continued to grow and evolve, fueled by the rich fats found in animal meat, up until about 12,000 years ago. It is at this point, correlating with the end of the Ice Age and a shift back towards agriculture and plant-based diets, that we observe an 11% reduction in brain size.” — Duru Bilimlier
