Researchers from the University of Georgia recently published their findings in the journal Psychological Science.
Fifty-one students took part in the study, each perform forming two self-control-testing tasks.
"The first task, which previous research has shown to deplete self-control, was tediously crossing out all the Es on a page from a statistics book. Then, participants performed what is known as the Stroop task where they were asked to identify the colour of various words flashed on a screen, which spell out the names of other colours," Forbes explains.
Before performing the Stroop test, half of the students rinsed their mouths with sugar-sweetened lemonade. The other half swished Splenda-sweetened lemonade. The researchers found that the students who rinsed with the sugary drink were faster at responding to the Stroop test than those who rinsed with the artificial sweetener.
Why the better performance? Researchers believe glucose — even when simply touching the tongue — triggers the brain's motivational centres.
"Researchers used to think you had to drink the glucose and get it into your body to give you the energy to (have) self control," says UGA psychology professor Leonard Martin, co-author of the study. "After this trial, it seems that glucose stimulates the simple carbohydrate sensors on the tongue. This, in turn, signals the motivational centres of the brain where our self-related goals are represented. These signals tell your body to pay attention."
Martin adds that glucose doesn't just boost energy levels, it boosts personal investment in current tasks.
"The glucose seems to be good at getting you to stop an automatic response such as reading the words in the Stroop task and to substitute the second harder one in its place such as saying the color the word is printed in," he says. "It can enhance emotive investment and self-relevant goals."
The study was small and will need further research, though Martin speculates that sugar water might help those trying to drop pounds or quit smoking.
In the meantime, curious individuals can always test the theory by gargling sugar water the next time they have to (begrudgingly) stay behind at work to get tedious work done.
If you try the swish-glucose method, let us know in the comments.
Watch the video below about the gluten-free craze that is sweeping North America.