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Yet Another Reason Why We're Fat

Try not to pass by a gym on your way to lunch — at least if there are signs in the window promoting the benefits of exercise. You may end up eating more.
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According to a new study, the act of receiving a message touting the benefits of exercise can cause people to unconsciously compensate by ingesting more food. If the researchers are correct, our unconscious mind does not differentiate between thinking about exercise and actually doing it: It simply reacts to the concept with the desire for more nourishment.

This suggests public-health campaigns urging people to get off their butts may have to be rethought. The majority of people who see such announcements but remain sedentary may actually be eating more than those who haven’t been exposed to the message.

The study, just published in the journal Obesity, was led by University of Illinois psychologist Dolores Albarracin. Expanding on previous research by John Bargh, Steven Pinker and N.A. King, she conducted two experiments to gauge the impact of messages that encourage exercise.

In the first, college students were exposed to a series of print advertisements, ostensibly so they could rate their appeal and effectiveness. Half of the students saw ads with such slogans as “join a gym” or “take a walk,” while the other viewed ads with exercise-neutral messages such as “make friends.”

Immediately afterward, they were given a second, purportedly unrelated task: to taste and rate raisins. Each was provided with 20 raisins and told they could eat as many as they desired.

Participants who looked at the ads promoting exercise ingested an average of 18.4 calories, compared to just under 12 calories for those who saw the neutral messages. In other words, they ate one-third more.

In the second experiment, words were subliminally flashed onto computer screens while participants performed a hand-eye coordination task. They then were offered small bowlfuls of M&Ms, raisins and peanuts. Those who imperceptibly received pro-exercise messages (via quick flashes of words such as “action” and “go”) consumed an average of 108 calories, compared to 87 calories for the control group.

Albarracin concedes it’s uncertain whether the results will hold up when larger amounts of food are consumed. But health educators and others concerned about the obesity epidemic will nonetheless find her results distasteful, if not distressing.

Her research provides further confirmation that our food intake is driven by largely unconscious desires, which can be triggered by factors beyond our awareness. It’s enough to make you lose your appetite.