Discoveries

September 01, 2022

Biting Off More

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Chewing food played an important role in human evolution, according to a new study.

Scientists recently tested how much energy humans spend masticating on food compared with our closest primate species, the New York Times reported.

Humans spend more than half an hour chewing every day, but chimpanzees and orangutans chew food for about 4.5 and 6.6 hours per day, respectively.

In their experiments, researchers outfitted participants with plastic hoods connected to tubes that measure oxygen and carbon dioxide from breathing. They explained that the gas exchange created by the metabolic process – where oxygen is used and CO2 is produced – was used to measure the energy output from chewing,

The team then gave volunteers two types of chewing gum – hard and soft – and asked them to chew them for 15 minutes each.

Their findings showed that the softer gum increased the individuals’ metabolic rates by roughly 10 percent compared with while they were resting. However, the harder gum resulted in a 15 percent rise.

The researchers noted that munching tougher food takes a lot of energy and the results highlight that the metabolic costs of chewing may have played an important role in human evolution.

Cooking, mashing food with tools, and cultivating crops that are suited for consumption may have reduced the evolutionary pressure for humans to be super-chewers, the authors said.

This story originally appeared in the September 01, 2022 newsletter, Choosing Forgiveness.