April 21, 2004 -- Normal people crave food the same way addicts crave drugs, a new study shows.
Earlier studies show that the brains of obese people -- like those of drug addicts -- are low on dopamine receptors. Dopamine is a brain chemical involved in feeling pleasure and reward. Having low numbers of receptors may be a way to compensate for chronically high levels of dopamine triggered by overeating or addictions. It might also be that low levels of receptors are what makes them more vulnerable to their addictive behaviors, say researchers.
The new findings show that constant exposure to food advertising -- and food itself -- makes our craving worse. Obese people may find this craving unbearable.
"These results could explain the deleterious effects of constant exposure to ... advertising, candy machines, food channels, and food displays in stores," study researcher Gene-Jack Wang, MD, says in a news release.
Wang suggests that by constantly keeping our brains in craving mode, these "food stimuli" make it very, very hard for us to resist eating more than we need. The findings appear in the April issue of NeuroImage.
Food Craving Lights Up Brain
Wang's team enrolled 12 healthy, normal-weight volunteers. The subjects didn't eat for 17 to 19 hours before the study.
The researchers then tempted them with their favorite foods, warmed up to make it smell appetizing. Cruelly, they even swabbed the subjects' tongues with tiny tastes of food.
As one might expect, this torment made the subjects' brains light up on the brain scan -- particularly a region called the right orbitofrontal cortex. This part of the brain also becomes active in cocaine-craving addicts.
"The high sensitivity of this brain region to food stimuli, coupled with the huge number and variety of these stimuli in the environment, likely contributes to the epidemic of obesity in this country," Wang says.