A Longitudinal Investigation of Psychological and Neural Mechanisms of Weight Loss

Abstract

Although obesity is fundamentally a problem of energy balance wherein calorie intake exceeds calorie output, there is a multitude of psychological and neural factors inherent in eating and overeating. Behavioral and neuroimaging research suggests a relationship between emotion regulation and eating behavior. However, the connections among psychological characteristics, brain function, and weight loss maintenance are poorly understood. Accordingly, in the present study, fMRI was used to examine how two psychological characteristics, emotion amplification and rumination, are related to (a) neural response to food images both before (baseline [BL]) and after (3M) participants undergo a three-month behavioral weight loss intervention, and (b) initial weight loss and weight loss maintenance. Emotion amplification was associated with decreased activation in dorsolateral prefrontal cortex (DLPFC) from BL to 3M. Rumination was associated with decreased activation in DLPFC from BL to 3M and increased activation in lateral prefrontal cortex, anterior cingulate cortex, parahippocampal gyrus, and amygdala from BL to 3M. Rumination was also inversely correlated with BL post-meal activation in DLPFC and caudate; activation in these two regions was prospectively associated with more weight loss from BL to 3M. Findings suggest that emotion amplification and rumination contribute to how food stimuli are processed at a neural level. Potential mechanisms for behavioral regulation and treatment implications are discussed.