Reward Capacity Predicts Leptin Dynamics During Laboratory-Controlled Eating in Women as a Function of Body Mass Index.

OBJECTIVE: The role of leptin in mesolimbic signaling of non-food-related rewards has been well established at the preclinical level, yet studies in humans are lacking. The present investigation explored the association between hedonic capacity and leptin dynamics and whether this association differed by BMI class.

METHODS: In this cross-sectional study of 75 women (42 with BMIs in the lean range and 33 with BMIs in the obesity range), serum leptin before and after meal consumption was measured. Reward capacity was assessed using the Snaith-Hamilton Pleasure Scale (SHAPS). Multiple regression tested whether reward capacity was associated with the leptin area under the curve (AUC), with an interaction term to test differences between the lean and obesity groups.

RESULTS: The interaction of SHAPS by BMI group was robust (β = -0.40, P = 0.005); among women with obesity, a greater SHAPS score was associated with a lower leptin AUC (β = -0.35, P = 0.002, adjusted R2  = 0.66). Among those in the lean group, the association was not statistically significant (β = -0.16, P = 0.252, adjusted R2  = 0.22). Findings were above and beyond BMI and age.

CONCLUSIONS: In this sample, a robust negative association between reward capacity and circulating leptin was stronger in women with obesity compared with lean counterparts. These findings suggest that despite likely leptin resistance, inhibitory leptin functioning related to nonfood rewards may be spared in women with obesity.