Does thinking make us fatter?

Angelo Tremblay noticed something odd every time he worked up a grant application for his research program in a Quebec university. He had a craving for chocolate chip cookies.

Now, thanks to research in his lab at the Universite Laval, he has a better understanding of why. It turns out that performing mental tasks, like trying to solve problems while working at a computer, stimulates the appetite so much that people tend to eat significantly more calories than they burned while performing the "knowledge-based" tasks.

In a study published in the current issue of Psychosomatic Medicine, researchers found a physiological basis for the spike in appetite. Mental work "destabilizes" the levels of insulin and glucose, two critical components in the body's regulatory and energy machinery, thus stimulating the appetite, said Jean-Philippe Chaput, lead author of the study.