Since chewing tougher food — or in this case, firmer gum — consumes more energy, these findings suggest that the metabolic costs of chewing may have played an important role in our evolution. Making food easier to process through cooking, mashing food with tools and cultivating crops improved for eating may have reduced the evolutionary pressure for us to be super chewers. Our evolving chewing needs may have shaped the shape of our faces.
“One of the things we really haven’t been able to figure out is why the human skull is so funny,” said Justin Ledugar, a biological anthropologist at East Tennessee State University who was not involved in the study. Compared to our closest relatives, our facial skeletons are precisely built of relatively small jaws, teeth and masticatory muscles. “All of this reflects a reduction in reliance on vigorous chewing,” he explained.
But, he added, our flat faces and short jaws make us bite more efficiently. “It makes the entire feeding process less costly from a metabolic standpoint,” said Dr. Ledugar. Humans have evolved ways to chew more intelligently and not with greater difficulty. Dr. Van Kastern, who hopes to continue his research using actual foods, says he’s excited about the possibility of learning more about how humans evolved.
“To know the environmental, societal, and nutritional reasons why we got here, it is infinitely interesting to me,” he said, “because it enables humanity to “try to work on the foggy path into the future.”