Imagination Diet: Thinking About Eating Kills Cravings

Dec. 9, 2010— -- This holiday season, visions of sugar plums dancing in your head, or any other treats for that matter, may be the best way to ensure that you don't overindulge, according to new research from Carnegie Mellon University.

While dieters have traditionally been told to avoid thinking about "bad" foods lest they boost cravings, researchers found that imagining eating a certain treat actually made participants eat less of it.

"There's a huge literature on craving and it all suggests that the more you think about something the more you crave it," says Carey Morewedge, the lead author and an assistant professor of social and decision sciences. "But we found that imagining the consumption of food actually significantly decreased the desire to consume it."

In the study, one group of participants was asked to imagine eating thirty M&Ms and imagine putting a quarter into a slot three times. Another group was asked to imagine eating just three M&Ms and placing thirty quarters, one by one, into a slot. Subjects were told that the study was about imagery and size perception so that they would not be overly conscious of their eating habits. When the experiment was over, each group was given access to a bowl of real live M&Ms, and told to help themselves.

Those who imagined eating thirty M&Ms (roughly the amount in a package of the candy) ate half as many M&Ms as those who had spent their time mostly imagining quarters.

Researchers then did a series of similar experiments and determined that just thinking about (but not thinking about eating) the candy didn't have this effect and that thinking about eating one food, like M&Ms, only affected the desire to eat that particular food, not any other treats.

While this discovery may not be of practical use to dieters yet, the study, published today in the journal Science, challenges old assumptions about cravings and the desire to indulge.

Desire, Cravings, and the Brain

So why would playing pretend with your favorite treat help you keep from overindulging?

Morewedge says he thinks it has to do with what happens in the brain when imagining experiences and the way the brain becomes habituated to repeated experiences.

There's another body of research that shows that imagining doing something and actually doing it trigger similar responses in the brain, he says. For instance, imagining a spider crawl across your leg triggers perspiration and other bodily reactions that would be seen if you were dealing with the real thing.

So by imagining eating food, your brain might react as if you are actually eating that food.

"What is going on here is in part due to dopamine release which may occur during the process of anticipating and imagining the consumption of a particular food," says Dessa Bergen-Cico, assistant professor of health and wellness at Syracuse University. Dopamine is a neurotransmitter that is associated with pleasure and satiety, so just thinking about ingesting the food might be helping satiety and craving, she says.

But, as the researchers show, that doesn't mean that imagining just one bite, or in the study's case, two or three M&Ms, is going to kill cravings. That's where habituation comes in.

"Habituation is a decreased physical and behavioral response to food," says Morewedge. "For instance, the tenth bite of pancakes is less desired than the first bite. People habituate to everything from the brightness of light in their room to the taste of their pancakes."

So by tricking the brain into experiencing what it's like to consume a particular food, the body starts to become habituated to the taste and enjoyment of eating it. By the time the real food comes around, the brain has already gotten sick of eating it earlier, so you eat less.

Playing Pretend With Your Diet?

"It's sort of 'eating vicariously' via their imaginations," says Dr. Keith Ayoob, associate professor at the Albert Einstein College of Medicine. This might help dieters stop stressing out over avoiding certain foods, Ayoob notes, because, "in a way, it allows them permission to imagine eating whatever they want. They stop playing tug-of-war with a particular food. Then when they finally get the food, they've already had a 'head start' on the experience so they may feel less need to overconsume it."

It's too early to tell if playing pretend with those hard-to-resist holiday treats could actually keep off those extra pounds, Morewedge says.

The effect only works on the specific food item imagined, so trying to dampen a craving for pumpkin pie would still leave you susceptible to sugar cookies, for instance. Also, as soon as another food is imagined, the habituation to the first food is wiped out.

"It's just not viable to imagine every kind of food at a holiday dinner, and as soon as you imagine the second one, it will wipe out the first," Morewedge says. Researchers also don't know how long the effects last.

But Morewedge suggests this kind of habituation could have implications for other types of cravings, such as those for cigarettes, drugs, and alcohol.

This might be a slippery slope, however, says Bergen-Cico. "The sight, smell and sounds associated with prior alcohol and other drug use cause very powerful cravings for addicts. Effective recovery includes learning to extinguish and ride out cravings," she says. "I think this would be an effective tool for food, but a dangerous approach for people with alcohol and other drug addictions."