According to a new study, a difference in brain activity patterns could explain why some people are able to maintain a significant weight loss while others regain the weight that was lost.
The results of this brain imaging study suggest that successful weight loss maintainers could learn to respond differently to food cues.
Long-term weight loss maintenance continues to be a problem in the treatment of obesity. Long-term weight loss maintenance continues to be a major problem in obesity treatment. Weight loss behavioral program participants lose an average of 8 to 10 percent of weight during the first six months of treatment and will maintain approximately two-thirds of their weight loss after one year. However, despite intensive efforts, weight regain appears to continue for the next several years, with most patients returning to their baseline weight after five years.
“Our findings shed some light on the biological factors that may contribute to weight loss maintenance. They also provide an intriguing complement to previous behavioral studies that suggest people who have maintained a long-term weight loss monitor their food intake closely and exhibit restraint in their food choices,” said lead author Jeanne McCaffery.
The 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 lbs and have 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. Specifically, 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.
“It is possible that these brain responses may lead to preventive or corrective behaviors, particularly greater regulation of eating, that promote long-term weight control,” said McCaffery.
References:
1. Jeanne McCaffery, et al. Differential functional magnetic resonance imaging response to food pictures in successful weight-loss maintainers relative to normal-weight and obese controls. Am. J. Clinical Nutrition, doi:10.3945/ajcn.2009.27924.
