Disordered eating partly mediates the relationship between poor sleep quality and high body mass index

Objective: We evaluated the relationship between poor sleep quality and high body mass index (BMI) in a community-derived sample. In addition, we explored the premise that disordered eating (i.e. eating late at night and/or binge eating, which can occur at night) may partly explain the relationship. Method: An online survey asked 330 participants about their height and weight, recent sleep quality, and recent experiences of binge-eating and night-time eating. Results: Using multiple regression analyses, high BMI was shown to be related to shorter sleep duration, increased sleep latency, use of sleeping medications and worse binge-eating, whereas worse sleep quality was related to worse night-eating, after controlling for depression and demographics. Using mediational analyses, binge-eating was shown to partly mediate the relationship between worse sleep quality to higher BMI, whereas night-eating mediated the reverse association of high BMI to worse sleep quality. Discussion: The results suggest that night- and/or binge-eating may partly explain the observed relationship between worse sleep quality and overweight/obesity. Thus, the relationship may simply reflect that overweight people are more likely to binge-eat while they wait for sleep to come, and this may contribute to weight gain over time. In addition, the results may indicate that eating rather than weight gain or obesity may be responsible for causing the sleep deficits in overweight people.