Neuronal and behavioral effects of an implicit priming approach to improve eating behaviors in obesity

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PROJECT SUMMARY/ABSTRACT Weight loss is associated with a reduction in obesity-related health risks, but can be difficult, with preventing subsequent weight regain even more challenging. As such, understanding mechanisms underlying energy balance regulation and identifying strategies for successful weight loss and maintenance are important goals, and are key components of the Strategic Plan for NIH Obesity Research. Food intake is a complex process involving homeostatic signals (e.g., appetite-related hormones) and non-homeostatic signals (e.g., reinforcing properties of food). One factor that may contribute to susceptibility to obesity is a high responsivity to high-calorie foods, which promotes increased caloric intake. Food preferences involve learned associations thought to develop via classical conditioning through repeated pairings with external stimuli. Improving our understanding of the neuronal mechanisms underlying these processes and attempting to modify them may be a useful strategy for weight loss and maintenance. Therefore, the proposed study aims to investigate the neuronal and behavioral effects of an intervention designed to alter affective associations with food, using a novel implicit priming (IP) paradigm, in which positively or negatively valenced images are presented immediately prior to food images, but not consciously perceived. We hypothesize that IP will alter neuronal and behavioral responses related to food intake, reducing the appeal of high-calorie foods and promoting weight loss and maintenance. The project goals are to further delineate the neuronal mechanisms underlying the intervention, establish the impact of IP on longer-term food preferences and eating behavior, and determine if it can facilitate weight- loss maintenance in individuals with overweight/obesity. Effects of IP on neuronal responses to visual food cues and measures of eating behaviors (food intake, preferences) will be measured not only acutely, but also following 12 weeks of weekly IP administrations, within the context of weight-loss maintenance. Weight and body composition will be measured before and after the intervention, and, to assess lasting effects, 12 weeks after the intervention has ended. Participants will be randomized to active IP, control IP (with scrambled images as primes), or to an active control, cue exposure therapy (CET). Sex-based differences will also be examined, as studies have observed women to have stronger, more frequent food cravings, greater neuronal response to hedonic food cues, and greater sensitivity to disgust than men. The use of neuroimaging in this study will provide a more sensitive measure than behavioral measures alone and will help to identify mechanisms through which the intervention changes behavior. If the project aims are achieved, it would not only yield new information about the neurobiology of food intake behavior, but also could represent a potential novel intervention for treatment and prevention of obesity.