Ever wondered how some people successfully maintain a significant weight loss, while others tend to regain the weight? Well, researchers at The Miriam Hospital attribute such tendencies to a difference in brain activity patterns.
The researchers showed that when individuals who had 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 behavioural control and visual attention, as compared to obese and normal weight participants.
The findings of the study suggest that successful weight loss maintainers may learn to respond differently to food cues.
"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 Dr. Jeanne McCaffery.
Long-term weight loss maintenance continues to be a major problem in obesity treatment.
Participants in behavioural weight loss programs lose an average of 8 to 10 percent of their 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.
The researchers used functional magnetic resource imaging (fMRI) 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.
When the participants were shown pictures of food items after a four-hour fast, it was found that 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. However, future research is needed to determine whether these responses are inherent within an individual or if they can be changed," said McCaffery.
The study has been published in the American Journal of Clinical Nutrition.