What is Night Eating Syndrome?
Night eating syndrome was first described by Dr. Albert Stunkard of the University of Pennsylvania in 1955.1 He started the Weight and Eating Disorders Program at the university and discovered that some of his patients who were being treated for overweight or obesity issues did not eat in the morning. Instead, they would eat massive amounts of food in the evening and overnight and he named it night eating syndrome.
For a diagnosis to occur, the night eating pattern has to be present for at least two months, and sufferers will typically eat more after supper than before or during it1. While the eating usually has an emotional aspect, there are differences with binge eating disorder. Here, the eating is continuous instead of a binge and sufferers tend to have difficulty sleeping through the night.
While night eating syndrome hasn't received much attention, estimates suggest as many as 10% of obese people could suffer from the disorder.
What are the Causes of Night Eating Syndrome?
A number of ideas have been proposed, and the two main possible causes of night eating syndrome are behavioral and biological in origin.2 Behavioral night eating syndrome causes are largely theoretical while some of the biological causes are supported by research.
Night eating syndrome seems to affect high achievers more than the normal population. The theory is that these people work through lunch and then overcompensate when they eat at night. This behavior probably begins in college, and the person is unable to change their distorted eating patterns once they start working a normal schedule.
Night eating syndrome may also be a response to dieting. Often, people who want to lose weight skip breakfast and eat a light lunch. At night, they give in to their hunger and overcompensate by eating large amounts of food, and this becomes a habit. There is also some speculation that stress may play a role in various night eating syndrome causes, but this relates more to the disorder's biological causes.
Researchers have found specific hormone imbalances among those with night eating disorder.3 A study conducted by Dr. Stunkard at the University of Pennsylvania found that melatonin is lower among night eaters, but two other hormones, leptin and cortisol are higher.
A separate study which was conducted in the University Hospital of Tromso, Norway and published in the Journal of the American Medical Association (JAMA) in 1999 found the same imbalances of melatonin, leptin, and cortisol.
The hormone melatonin is important for regulating the sleep cycle, and cortisol is released in response to stress. Leptin appears to be important for appetite regulation, but the scope of its function is still unclear.
It is not known if a change in the level of one hormone triggers a change in the others, or if the levels of each hormone change around the same time. Somehow, these imbalances lead to the onset of night eating syndrome. Ongoing research is trying to figure out the nature of the relationship between the three hormones and how they trigger/cause the disorder.