"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 coauthor Leonard Martin, professor of psychology. "After this trial, it seems that glucose stimulates the simple carbohydrate sensors on the tongue." He adds: "This, in turn, signals the motivational centers of the brain where our self-related goals are represented." And it's these signals, he adds, that wake your body up and tell it to start paying attention.