Rethinking Evolution: Carbs, Not Meat, Built the Human Brain

Research over recent years challenges the long-held belief that meat consumption was the primary driver of human brain evolution, suggesting instead that carbohydrates played a crucial role. Studies indicate that early humans and their relatives, such as Neanderthals, adapted to starch-rich diets much earlier than previously thought, providing the necessary energy for brain development.

A study from Harvard University analysed the oral microbiomes of Neanderthals and ancient humans, revealing that they consumed starch-rich foods as far back as 100,000 years ago. This early dietary shift likely supplied the glucose essential for brain growth, indicating that carbohydrates were a significant part of the pre-agricultural human diet.

Another recent study published in Nature Ecology & Evolution examined the dietary habits of the Later Stone Age population in North Africa. Isotopic evidence revealed a high reliance on plant-based foods, casting doubt on long-held beliefs about the so-called ‘Paleo’, meat-heavy diets of early humans.

An analysis of nitrogen isotopes in the tooth enamel of Australopithecus individuals, who lived around 3.5 million years ago, shows no evidence of meat consumption. This finding indicates that these early human ancestors were primarily plant eaters.

Additionally, researchers have traced the genetic evolution of the AMY1 gene, responsible for producing amylase—an enzyme that breaks down starches—to over 800,000 years ago. This adaptation suggests that early humans had a high-starch diet long before the advent of agriculture, challenging the notion that a protein-rich diet was solely responsible for increased brain size.

These findings collectively suggest that plant foods and carbohydrates, rather than meat, were instrumental in the development of the human brain. Early humans’ ability to digest and utilize starches provided the necessary energy for cognitive evolution, highlighting the importance of plant-based foods in our ancestral diet.