The Night Eating Syndrome (NES) in Bariatric Surgery Patients.

The night eating syndrome (NES) has been included into the Diagnostic and Statistical Manual of Mental Disorders 5 as an example of an 'other-specified feeding or eating disorder'. The prevalence of NES has found to be higher in obese populations than in the general population and seems to rise with increasing body mass index. Recent studies suggest a prevalence of 2%-20% in bariatric surgery samples. Given that the core feature of this eating disorder may involve a shift in the circadian pattern of eating that disrupts sleep, and not the ingestion of objectively large amounts of food, it is a pattern that can continue after bariatric surgery. Nonetheless, symptoms of NES appear to decrease after weight loss surgery, and there is no evidence that pre-surgery NES negatively impacts weight loss following surgery. Prospective and longitudinal studies of the course of night eating symptoms are warranted using clear criteria and standardized assessment instruments.