Cognitive Decline and Mental Distress: A Potential Mismatch between the Contemporary Diet and the Evolved Brain

Archeological studies describe that human cognition evolved with the increase in human brain size. Evidence also suggests that our ancestors' diet, which was a high-energy-nutrient-dense diet, contributed significantly to the complexity of the brain as dietary components act as structural and functional precursors. Therefore, the brain requires a repertoire of nutrient-dense food to grow, maintain and repair different brain structures. Additionally, ancestor males and females had different physical responsibilities that may have necessitated different energy requirements and may have led to a disparity in food consumption. Therefore, the gender-based differential food consumption of our ancestors and their energy intake may explain the differential brain connectivity between human males and females. Therefore, a potential mismatch may exist today between contemporary diet and the evolved brain which may be contributing to cognitive decline and mental distress in humans. Hence, the purpose of this review is to explore the evidence in the literature that potentially supports this hypothesis to better understand the role of diet on brain health.