The question: Most experts agree that sugar is rightfully demonized for causing a host of health woes that extend well beyond the obesity epidemic. But sugar, especially taken in moderation, has its defenders, who argue that it's actually the brain's preferred fuel source — a natural reward system devised by Mother Nature to help you get things done. Some studies have concluded that drinking a glass of something sweet provides a temporary brain boost. In new research published in the journal Psychological Science, experts at the University of Georgia wanted to see if just the taste of sugar could improve a person's focus and self-control.

How it was tested: Researchers recruited 51 students and tasked them with some basic feats. Some of the students were told to rinse their mouths with lemonade made with real sugar, while a control group gargled lemonade made with Splenda. No actual swallowing: Both groups were asked to spit the lemonade out. First, researchers asked participants to scan a page from a statistics book and meticulously cross out all instances of the letter E. The next task was something called a Stroop task: Participants were shown colored words that spelled out the name of a different color (for instance, blue letters that spelled out the word "red"). The goal, says Forbes, was to shut off the "tendency to read the words (which is easy to do) and instead see the colors (which is harder to do)." Subjects were timed as they completed both tasks.

The outcome: Students who had rinsed their mouths with sugar-sweetened lemonade performed significantly faster than the other group, suggesting that genuine glucose can trigger the brain's motivational centers simply by touching the tongue. 

What experts say: "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," said co-author Leonard Martin. "After this trial, it seems that glucose stimulates the simple carbohydrates sensors on your tongue," which "signals the motivation centers of the brain where your self-related goals are represented." In other words, these signals "tell your body to pay attention."

The lesson: It's late, but you still have a pile of work to do. To give yourself a lift, try gargling something sugary to stimulate the brain's focus areas — then spit the stuff out to preserve your waistline and avoid a sugar crash. "It doesn't crank up your energy," adds Martin, "but it cranks up your personal investment in what you are doing."