Chewing can increase your body's energy use by up to 15 per cent

Researchers used a plastic dome placed over people’s heads to measure how much energy they expended chewing gum versus sitting idly. They found chewing gum uses a significant amount of energy

By Jason Arunn Murugesu

Chewing uses a surprising amount of energy. An experiment that looked at the energy use associated with chewing gum found that it can increase bodily energy expenditure by up to 15 per cent.

Adam van Casteren at the University of Manchester in the UK and his colleagues measured energy use in 21 people between 18 and 45 years old as they chewed gum for 15 minutes.

The gum was tasteless, calorie-free and odourless. “This way it doesn’t activate the digestive system to the same extent as it otherwise would,” says van Casteren. “We wanted to measure just chewing or as close to chewing as we could get.”

Each participant was asked to chew two types of gum – one soft and the other stiff – so they could compare the effects of the gum’s properties on the participants’ energy expenditures.

Energy expenditure was measured using a plastic dome covering the participants’ heads. A monitor inside the dome measured oxygen intake and the amount of carbon dioxide released. “You can use this information to work out how much energy is being expended,” says van Casteren.

Before the experiment, the participants had all worn the plastic dome while they sat watching a film in order for the researchers to capture their base level energy expenditures.

The researchers found that chewing the soft gum elevated energy expenditure by about 10 per cent, while chewing the stiffer gum increased this expenditure by around 15 per cent. Van Casteren says it’s interesting that a small change in the properties of the gum had such a notable effect on energy expenditure.

He says he expects the energy used to chew real food will be even larger as many foods such as steak and nuts require a lot of effort to break down. “I want to look at how much energy chewing nuts and seeds expends next,” he says.

The findings suggest that the energy expenditure required to chew may also explain why we developed such strong teeth and jaws for the action. Any amount of energy lost while chewing food, makes the meal a less efficient source of energy.

Dylan Thompson at the University of Bath in the UK says the increase is still only a small amount overall. “It will contribute less than 1 per cent of total daily energy expenditure because of relatively short daily chewing times,” he says.

Thompson says the results are similar to a study he conducted in 2019 which found that standing for 20 minutes increased energy expenditure by about 12 per cent.

Journal reference: Science Advances, DOI: 10.1126/sciadv.abn8351