Negative affect mediates the association between nightly sleep disturbance and next-day binge eating.

Sleep disturbance has been linked with both increased negative affect and engagement in binge-eating (BE; i.e., eating episodes accompanied by a subjective sense of loss-of-control over eating). Negative affect itself is also predictive of BE. As such, it is possible that the effect of sleep disturbance on BE can be explained by increases in negative affect. We recruited adults with clinically significant BE (N = 96, M = 41.9 ± 14.1, 80.4 % female) to complete seven ecological momentary assessment surveys per day assessing sleep disturbance (morning surveys only), negative affect, and BE over 7-14 days. Mediation models evaluated whether there was an indirect effect of within-person increases in negative affect prior to binge eating on the association between within-person sleep disturbance (i.e., poor sleep quality, heightened morning fatigue, and short sleep duration relative to one's average) and binge eating. Pre-binge levels of negative affect mediated the association between both sleep quality (Est = -0.019, S.E. = 0.009, p = 0.028) and morning fatigue (Est = 0.020, S.E. = 0.009, p = 0.024) and BE. Negative affect did not significantly mediate the association between sleep duration and BE. Negative affect may be one mechanism linking sleep disturbance and BE. These findings suggest that treatments targeting sleep disturbance merit evaluation in eating disorder populations as they could eliminate sleep-related NA as a driver of BE. Future research should include objective assessment of sleep and test the additive benefit of interventions targeting sleep for BE.