PROVIDENCE, R.I.—A difference in brain activity patterns may explain why some people are able to maintain a significant weight loss while others regain the weight, according to a new brain imaging study by researchers with The Miriam Hospital.
The study, published in the American Journal of Clinical Nutrition, reported that when individuals who have kept the weight off for several years were shown pictures of food, they were more likely to engage the areas of the brain associated with behavioral control and visual attention, compared to obese and normal weight participants. Researchers suggest successful weight-loss maintainers may learn to respond differently to food cues.
Researchers used functional magnetic resource imaging (fMRI), a non-invasive technique that localizes regions of the brain activated during cognition and experience, to study the brain activity of three groups—18 individuals of normal weight; 16 obese individuals (defined as a body mass index of at least 30); and 17 participants who have lost at least 30 pounds and successfully maintained that weight loss for a minimum of three years.
After a four-hour fast, to ensure participants would be hungry, they were shown pictures of food items, including low-calorie foods (such as whole grain cereals, salads, fresh vegetables and fruit); high-calorie foods (including cheeseburgers, hot dogs, French fries, ice cream, cake and cookies), and nonfood objects with similar visual complexity, texture and color (e.g., rocks, shrubs, bricks, trees and flowers). The MRI scan documented brain responses to each image.
Those in the successful weight-loss maintenance group responded differently to these pictures compared to the other groups. Researchers observed strong signals in the left superior frontal region and right middle temporal region of the brain—a pattern consistent with greater inhibitory control in response to food images and greater visual attention to food cues.