Magnetic stimulation of a brain area may increase cravings for high-calorie snacks and make people eat more of those foods when given the opportunity, according to a new study.
Researchers at University of Waterloo, Canada found that after stimulation of the dorsolateral prefrontal cortex (DLPFC), a brain area involved in "executive function", young women experienced increased cravings for high-calorie snacks.
The results suggest that interventions aimed at enhancing or preserving DLPFC function may help to prevent obesity and related diseases.
The study included 21 healthy young women, selected because they reported strong and frequent cravings for chocolate and potato chips. Such "appetitive," calorie-dense snack foods are often implicated in the development of obesity.
The women were shown pictures of these foods to stimulate cravings. The researchers then applied a type of magnetic stimulation, called continuous theta-burst stimulation, to decrease activity in the DLPFC.
Previous studies have suggested that DLPFC activity plays a role in regulating food cravings.
After theta-burst stimulation, the women reported stronger food cravings - specifically for "appetitive" milk chocolate and potato chips.
During a subsequent "taste test," they consumed more of these foods, rather than alternative, less-appetitive foods (dark chocolate and soda crackers).
Stimulation to weaken DLPFC activity was also associated with lower performance on a test of inhibitory control strength (the Stroop test).
Decreased DLPFC activity appeared to be associated with increased "reward sensitivity" - it made the participants "more sensitive to the rewarding properties of palatable high caloric foods," the researchers said.
At the "basic neurobiological level," the study provides direct evidence that the DLPFC is involved in one specific aspect of food cravings: reward anticipation.
People with weak executive function may lack the dietary self-control necessary to regulate snack food consumption in "the modern obesogenic environment."
Faced with constant cues and opportunities to consume energy-dense foods, such individuals may be more likely to become overweight or obese.
The study appears in Psychosomatic Medicine: Journal of Biobehavioral Medicine, the official journal of the American Psychosomatic Society.
