Photograph by Greg Dale, National Geographic
December 9, 2010
Fighting an M&M's craving this holiday season? Let that milk chocolate melt in your mind—not in your mouth.
According to new research, imagining eating a specific food reduces your interest in that food, so you eat less of it.
This reaction to repeated exposure to food is called habituation, and it's well known to occur while eating. A "tenth bite of chocolate, for example, is desired less than the first bite," the study authors note.
But the new research is the first to show that habituation can occur solely via the power of the mind.
"A lot of people who diet try to avoid thinking about stimuli they crave. This research suggests that may not be the best strategy," said study leader Carey Morewedge, a psychologist at Carnegie Mellon University in Pittsburgh.
"If you just think about the food itself—how it tastes, smells, and looks—[that will] increase your appetite," Morewedge said.
"This research suggests that it might be better, actually, to force yourself to repeatedly think about tasting, swallowing, and chewing the food you crave to reduce your cravings."
What's more, the technique works with only the food you've imagined, he added. For instance, imagining eating chocolate wouldn't prevent you from gorging on cheese.
Mind Over Chocolate
Morewedge and colleagues conducted five experiments, all of which revealed that people who repeatedly imagined eating chocolate or cheese would eat less of that food than people who pictured eating the food fewer times, eating a different food, or not eating at all.
In one experiment, for instance, 51 subjects were divided into 3 groups. One group was asked to imagine inserting 30 quarters into a laundry machine—which requires the same motor skills as eating M&M's, the study says—and then eating three M&M's.
Another group was asked to imagine inserting three quarters into a laundry machine and then eating 30 M&M's. Lastly, a control group imagined just inserting 33 quarters into a laundry machine—no M&M's.
All participants then ate freely from bowls containing 1.5 ounces (40 grams) of M&M's each. When the subjects said they were done, the bowls were taken away and weighed.
The results showed that the group that imagined eating 30 M&M's each ate fewer of the chocolates than both the control group and the group that imagined eating 3 M&M's.
The study is part of a new area of research looking into the triggers that make us overeat, Morewedge noted.
Physical, digestive cues—that full-belly feeling—are only parts of what tells us that we're finished a meal. Recent research suggests that psychological factors, such as habituation or the size of a plate, also influence how much a person eats.
Such experiments are important as obesity rates climb—in the United States, for instance, nearly 30 percent of adults were obese in 2009, according to the U.S. Centers for Disease Control and Prevention. Obesity increases chances of Type 2 diabetes, heart disease, stroke, and other ailments.
The new study, Morewedge said, may lead to new behavioral techniques for people looking to control overeating or other addictive behaviors such as smoking.
The food-imagining study appears tomorrow in the journal Science.
A new species of dinosaur-era reptile is rewriting the books on the evolution of so-called sea monsters, a new study claims.
The world's highest peak has been shedding snow and ice for the past 50 years, possibly due in part to global warming, new research shows.
Detailed scans capture transformation.