Chewing Uses More Energy Than You Think | Smart News
We might not consider chewing a strenuous activity, but new research suggests it uses a surprising amount of energy. The way we grind our food may even have played a role in the evolution of humans.
In a study published in Scientists progress, the researchers fitted 21 participants with astronaut-like plastic helmets and measured their metabolic rate, or the amount of energy their bodies used, as they chewed.
But the participants weren’t given a five-course meal – they chewed tasteless, odorless gum.
“That way it doesn’t activate the digestive system to the same extent that it otherwise would,” says co-author Adam van Casteren, a biomechanics researcher at the University of Manchester in the UK. new scientist‘by Jason Arunn Murugesu. “We wanted to measure just the chew or as close to the chew as possible.”
The volunteers first lay down in the bubble-shaped hood for 45 minutes to provide a baseline measurement. Then they chewed two types of gum, one softer and the other stiffer, for 15 minutes while the researchers measured exhaled carbon dioxide, a sign of energy consumption. They found that the softer rubber caused a 10% increase in participants’ metabolic rate, while the stiffer rubber caused a 15% increase.
“I thought there wouldn’t be such a big difference,” van Casteren told the New York Times‘Kate Golembiewski. “Very small changes in the material properties of the item you’re chewing on can lead to quite substantial increases in energy expenditure, and that opens up a whole universe of questions.”
Compared to other mammals like cows, orangutans or especially pandas – which can spend 12 hours a day munching on bamboo – humans spend much less time chewing, on average only about 35 minutes a day, writing Reverseis Allison Parshall.
Food eaten by our elders Homo the ancestors would “certainly have required greater chewing effort to process orally,” the authors write. But modern humans and our more recent predecessors cooked and used tools, which made chewing easier. When this happened, the structure of their teeth and jaws changed, becoming smaller than that of other primates, according to Sciences Andre Curry.
Callum Ross, a University of Chicago anatomist who was not part of the study, says Science he is not convinced that energy consumption alone can explain the evolution of our teeth and jaws.
“Natural selection probably cares more about not wearing down your teeth than energy efficiency,” he told the publication. Still, he says, the new study is a starting point.
Van Casteren wants his future research to examine how much energy chewing real food, rather than regular gum, exerts, and he’s also looking forward to discovering more about human evolution, he tells the Time.
“Knowing the environmental, societal and food causes that led us to get here is just infinitely interesting to me,” he told the newspaper.