New Study Links Sugar Consumption to Human Brain Evolution

In a paper published in Science, Jennie Brand-Miller and colleagues used existing measurements of hominin brain size and fossil evidence of diet to estimate the proportion of sugars, proteins, fibers, starches and fats consumed by early humans. Their model, spanning from the bipedal Australopithecus afarensis to present-day foraging societies, indicates that sweet foods—principally fruit and honey—could have supplied as much as 66% of energy for the earliest hominins and about a quarter of total calories over the course of evolution.

The researchers stress that animal-derived nutrients were also important, framing human nutrition as a balance of protein, fat and carbohydrates. Anthropologist Matt Sponheimer, not involved in the study, highlighted its usefulness for generating new hypotheses but cautioned that the analysis rests on speculative dietary reconstructions, such as assuming Lucy’s diet resembled that of modern chimpanzees. The findings align with broader scientific consensus that early humans were not primarily carnivorous and underscore the biological basis for humans’ preference for sweetness and reliance on vitamin C from fruits.