Weight Suppression, Brain Reward Response to Food Cues, and Bulimic Behaviours: A Pilot fMRI Study

OBJECTIVE: Weight suppression (WS), or the difference between one's highest past and current weights, may help maintain bulimia nervosa (BN) by altering reward response to food cues. This pilot study tested associations among WS, brain reward activation to food cues, and BN behaviours. METHODS: Twenty women with BN were shown images of milkshake or tasteless control solution, followed by receipt of the corresponding beverage during fMRI. Regressions examined associations between brain activation in a priori regions of interest and WS and BN behaviours (i.e., objective binge-eating episodes, self-induced vomiting episodes, dietary restraint), corrected at k = 333, p < 0.010. Correlations examined the association between WS and BN behaviours. RESULTS: Upon consumption of milkshake versus control solution, WS positively associated with activation in the left caudate (k = 361, p = 0.001). WS also positively associated with binge eating (r = 0.52, p = 0.019), purging (r = 0.48, p = 0.032), and restraint (r = 0.53, p = 0.017). No BN behaviours associated with brain activation upon anticipation or consumption of milkshake (all ps > 0.010). DISCUSSION: Given the caudate's role in hedonic eating, the WS-caudate association may help maintain BN behaviours, such as binge eating. Although we failed to find an association between BN behaviours and caudate activation, our sample size was small. Therefore, we encourage replication in larger samples.