While most people take in their last round of daily calories before nighttime, up to 5.7% of the general population1 has a disorder that cause them to consume at least a quarter of their calories after dinner. In night eating syndrome (NES), “the circadian rhythm of eating is shifted toward later in the day such that daily caloric intake is minimized with increased food intake” at night.1
Features of the disorder may include strong urges toward nocturnal eating — typically during nighttime awakenings, lack of morning appetite and depressed mood. Insomnia is common among sufferers, and they may also have an additional feature associated with the disorder: the belief that they must eat in order to go to sleep or fall back to sleep.
Though NES was considered for inclusion as a new diagnosis in the “Feeding and Eating Disorders” section of the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), it ultimately was not recognized as a separate diagnosis. It is, however, listed under a new category called “Other Specified Feeding and Eating Disorder,” as one of several possible disorders that do not meet the full criteria for another eating disorder but cause significant impairment nonetheless.2 (This category, along with another new one called “Unspecified Feeding and Eating Disorder,” replaced the previous, broader category of “Eating Disorders Not Otherwise Specified.”)
Though it may share common features with sleep-related eating disorder (SRED) and binge eating disorder (BED), NES is a distinct disorder. SRED is a parasomnia in which “patients describe eating in an out-of-control manner with preference for high-caloric foods and sometimes with inedible or toxic items,” as described in a recent review in Psychiatry and Clinical Neurosciences.3