Pilot randomized trial demonstrating reversal of obesity-related abnormalities in reward system responsivity to food cues with a behavioral intervention

Abstract

Objectives:Obesity is associated with hyperactivation of the reward system for high-calorie (HC) versus low-calorie (LC) food cues, which encourages unhealthy food selection and overeating. However, the extent to which this hyperactivation can be reversed is uncertain, and to date there has been no demonstration of changes by behavioral intervention.Subjects and methods:We used functional magnetic resonance imaging to measure changes in activation of the striatum for food images at baseline and 6 months in a pilot study of 13 overweight or obese adults randomized to a control group or a novel weight-loss intervention.Results:Compared to controls, intervention participants achieved significant weight loss (−6.3±1.0 kg versus +2.1±1.1 kg, P<0.001) and had increased activation for LC food images with a composition consistent with that recommended in the behavioral intervention at 6 months versus baseline in the right ventral putamen (P=0.04), decreased activation for HC images of typically consumed foods in the left dorsal putamen (P=0.01). There was also a large significant shift in relative activation favoring LC versus HC foods in both regions (P<0.04).Conclusions:This study provides the first demonstration of a positive shift in activation of the reward system toward healthy versus unhealthy food cues in a behavioral intervention, suggesting new avenues to enhance behavioral treatments of obesity.

GLP-1 receptors exist in the parietal cortex, hypothalamus and medulla of human brains and the GLP-1 analogue liraglutide alters brain activity related to highly desirable food cues in individuals with diabetes: a crossover, randomised, placebo-controlled trial

“…Insular activity has been shown to be modulated with ratings of hunger and fasted/fed states [34, 35], indicating a role in the salience of food images similar to the parietal cortex, consistent with its activity during non-food salient stimuli [36]. Some studies have suggested that the putamen may be involved in the reward processing of food [15, 37–39] and have shown links between activation in the putamen and future weight gain [38]. Thus, since these areas decrease in activation on liraglutide, we would assume that participants find highly palatable foods less rewarding or relevant while on liraglutide.…”

Neural vulnerability factors that increase risk for future weight gain.

“…The evidence that weight gain is associated with down-regulation of dopamine-based reward circuitry dovetails with evidence that weight loss increases D2 receptor availability in humans (Steele et al, 2010) and rats (Thanos et al, 2008), and responsivity of reward circuitry to food cues (Cornier et al, 2012; Deckersbach et al, 2014; Rosenbaum et al, 2008), though one study reported that weight loss was associated with a reduction in D2 receptor availability (Dunn et al, 2010). For the most part, this literature also seems consistent with the thesis that habitual overeating results in down-regulation of reward circuitry and that reducing overeating can reverse this process.…”

“…Weight loss has also been associated with concurrent reductions in food preference ratings for high-calorie foods relative to changes observed in waitlist controls (Deckersbach et al, 2014). …”

Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity

“…4, 346, 392-394 Even the brain's unconscious reward/craving (“addiction”) centers are plastic and can be trained to respond to healthful rather than unhealthful foods. 395 Furthermore, for the food industry, the success or failure of specific products has often depended not on differences in contents of fat, sugar, or salt, but on the prowess and power of their convenience, packaging, marketing, and promotion. 396 Undoubtedly, taste plays a role in consumer choice, but so do availability, price, packaging, marketing, convenience, and culturally-driven perceptions of norms, status, and prestige.…”