According to a new study co-authored by researchers from the University of Sydney, starchy carbohydrates are thought to have been integral to the evolution of the human brain as we know it.
As part of the Charles Perkins Centre and Faculty of Agriculture and Environment, researchers published a study in the Quarterly Review of Biology, that challenges long-standing theories surrounding brain development.
The theory goes, that the increase in size of the human brain, around 80,000 years ago, was due to increased meat consumption.
This research throws a spanner in the works of most paleo-centric arguments, claiming that it was indeed the paleo’s starchy nemeses that were responsible in evolving the human brain.
“Global increases in obesity and diet-related metabolic diseases have led to enormous interest in ancestral or ‘Palaeolithic’ diets,” said Professor Jennie Bran-Miller from the Charles Perkins Centre, who co-authored the research with Professor Les Copeland from the University of Sydney’s Faculty of Agriculture and Environment and international colleagues.
“Up until now, there has been a heavy focus on the role of animal protein in the development of the human brain over the last two million years. The importance of carbohydrate, particularly in the form of starch-rich plant foods, has been largely overlooked. Our research suggests that dietary carbohydrates, along with meat, were essential for the evolution of modern big-brained humans.
“The evidence suggests that Palaeolithic humans would not have evolved on today’s ‘Paleo’ diet.”
Part of the study suggests that the high glucose demands required for the adequate development of humans’ large brains, would not have been met on a low carbohydrate diet.
According to research, starches like tubers, seeds and some fruits were readily available to early humans. But, with the advent of cooking, came the real change in human evolution.
“Cooking starchy foods was central to the dietary change that triggered and sustained the growth of the human brain,” Professor Copeland said.
“After cooking became widespread, starch digestion advanced and became the source of preformed dietary glucose that permitted the acceleration in brain size.”
“In terms of energy supplied to an increasingly large brain, increased starch consumption may have provided a substantial evolutionary advantage.”
Co-author Karen Hardy, a researcher with the Catalan Insitute for Resaerch and Advanced Studies at the Universitat Autònoma de Barcelona, said: “We believe that while meat was important, brain growth is less likely to have happened without the energy obtained from carbohydrates. While cooking has also been proposed as contributing to early brain development, cooking carbohydrates only makes sense if the body has the enzymic equipment to process these.”
Therefore, researchers have surmised that, unilike the modern paleo diet, we should incorporate underground starchy foods such as taro, yams, sweet potatoes and potatoes, as well as grains like wheat, rye, barley, corn, oats, quinoa and millet.
“It is clear that our physiology should be optimised to the diet we experienced in our evolutionary past,” Professor Brand-Miller said.
“Eating meat may have kickstarted the evolution of bigger brains, but cooked starchy foods, together with more salivary amylase genes, made us smarter still.”