Glucose Mouth Rinse Really Does Enhance Self-Control

That weird study we wrote about a couple of months ago just got reinforced.

Undoubtedly the oddest piece of research we’ve reported on in a while is an Australian study that found gargling with a glucose solution helps people renew their self-control. Even as I wrote the piece, I could hear the sarcastic voice of Paula Poundstone in my head, making fun of it on Wait Wait Don’t Tell Me.

Well, guess what? A group of American researchers has come to the same conclusion.

Writing in the journal Psychological Science, a research team led by University of Georgia psychologist Matthew Sanders describes an experiment featuring 51 students. They began by performing a tedious task that has been shown to deplete self-control, which involves “following a complex rule to cross out Es on a page from a statistics book.”

They then performed the well-known Stroop task, in which they were instructed to quickly identify the color of various words that were flashed on a screen—some of which spelled out the name of a different color.

In a neat bit of multitasking, they did so while rinsing out their mouths with lemonade. Half used lemonade sweetened with glucose; the others used lemonade sweetened with Splenda.

Compared to those with the sugar substitute swishing around in their mouths, participants rinsing with glucose were significantly faster to identify the incongruent words (that is, those where the word "green" was spelled out in blue letters). Somehow, without entering their bloodstreams, the glucose apparently replenished their self-control, allowing them to efficiently focus on the task at hand.

So if you just can’t get yourself to do something that needs to be done—or, conversely, can’t resist reaching for that cigarette or chocolate bar—a glucose rinse may be the answer. As Sanders and his colleagues note, it apparently activates “brain areas associated with reward, which, in turn, increases participants’ motivation.”

And with zero calories!