Night-eating syndrome (NES), also referred to as night-binging disorder (NBD), is a misunderstood eating disorder that is often linked to the binge-eating disorder (BED) – even though the two conditions are distinctly different.
It is possible, however, for a person to experience both disorders (NES and BED) at the same time, hence NBD. Still, it is important to understand that NES does not always result in obesity, whereas BED is more likely to be linked to an elevated body mass index (BMI). NES is characterized by the act of eating more after (not during) an evening meal.
Dr. Albert Stunkard originally coined the term, “night-eating syndrome” in 1955. He later went on to extensively publish numerous journal articles on topic.
There is a clinical component to the diagnosis of NES. In fact, criteria established during the International Symposium of 2008, also includes “evening hyperphagia” (excessive eating), which is defined as food consumption that is greater than or equal to 25% of one’s total daily calories, after dinner and/or during night-time awakenings.
One must consume large quantities of food and experience at least 3 of the following 5 criteria to be diagnosed with NES:
1. Morning Anorexia
3. A Desire to Eat In-Between Dinner and Bedtime
4. A Need to Eat to Fall Asleep or Return to Sleep
5. Depressed Mood (Mostly at Night). (2)
Night-eating syndrome (NES) affects approximately 1.5% of the population and is equally common in men and women, according to the National Institute of Mental Health. However, the incidence of NES is higher in certain sub-populations (i.e. those with psychiatric disorders and those, who have had gastric stapling).
Researchers at the University of Pennsylvania School of Medicine suggest that approximately 6% of those who seek treatment for obesity have NES. Similarly, a recent study found that more than a quarter (27%) of people who are overweight by at least 100lbs have NES.
Signs & Symptoms
Listed below are the signs and symptoms of NES:
• Poor morning appetite or absent or delayed first meal of the day (i.e. not eating until many hours after waking up)
• Not eating a lot during dinner, but snacking a lot afterwards
• Frequently waking up from sleep to snack
• Feeling anxious, upset, tense, and/or guilty, during and after eating
• Unable to fall or stay asleep at night
• Having a high stress level, depression, and/or anxiety
• Not binging food, but rather consuming a steady supply of food during the evening hours
• Consuming starchy foods, carbohydrates, and/or sweets on a regular basis
• Waking up at night three or more times a week to eat
• Believing that eating will help you sleep better
• Remembering that you awakened and started eating, as opposed to sleep-walking and eating
Causes & Risk Factors
The cause of night-eating syndrome varies, however there are usually a plethora of contributing factors. For example, it could arise once a college student develops a habit of eating late at night. And even if the college student wants to break the habit after college, it may be hard to break, persisting into adulthood. Or an individual may develop a habit of eating late at night because he/she doesn’t get off from work until late at night (after 8pm).
Still, some individuals may develop night-eating syndrome (NES) because they work through their lunches. And because they are starving when they get off from work, they overindulge and/or overcompensate for the missed lunches by eating more at night. It is important to understand that daytime dieting (i.e. reduced food intake or skipping meals) can send mixed signals to the brain. In other words, it can tell your brain that your body needs more calories at night to function properly – when it really doesn’t.
Keep in mind, there are two “brain chemicals,” leptin and insulin, that play a significant role in appetite and hunger. And night-time sleep is the time that your body uses to “fast” for a prolonged time (usually 6-10 hours). It is during this time that hormonal changes help balance and maintain your energy level.(13) Individuals with NES, however, typically experience reduced leptin levels at night, which may contribute to nocturnal awakening and indigestion. These individuals also tend to have lower levels of ghrelin, “the hunger hormone” in their bodies. Moreover, low levels of melatonin have been implicated during NES’s desynchronization process.(14, 15, 16)
According to one study, there is a link between sleep-wake cycle preferences. In other words, people, who are “early risers” and who also go to bed early, usually don’t skip breakfast, as compared to “late birds,” who tend to skip breakfast due to late night snacking or eating (Sato-Mito et al.,2011; Horne & Ostberg, 1976; Roenneberg et al., 2007). As a result, some researchers suggest that people who are “early risers” have better control and flexibility in regulating their food intakes (Fleig & Randler, 2009; Schmidt & Randler, 2010).
Although “eating behaviors” have been linked to circadian rhythm (sleep rhythm) or one’s internal clock (Garaulet & Madrid, 2010), the connection between nutrition, metabolism, and obesity, in conjunction with NES is still unclear. But according to one report, consuming 25% of your food intake after your evening meal is enough to garner a diagnosis of NES (Allison et al., 2010).
In addition, a heavy preference for carbohydrates can produce “feel good” chemicals or “happy hormones” in the body, which suggests that night-time eating may be an unconscious attempt to self-medicate or escape from problems. It is also important to understand that NES may run in families. Thankfully, however, it appears to respond to SSRI sertraline treatment.
Multiple studies have suggested that serotonergic (SSRIs) agents and psychological interventions, such as cognitive behavioural therapy (CBT) are effective in treating NES. Among the SSRIs, sertraline had the most positive results. Sertraline is also used to treat depression, while topiramate and agomelatine may be beneficial for night-eating syndrome. Similarly, the benefits of phototherapy may help reduce symptoms.
Results from a recent study indicated that non-obese patient with NES and depression,who underwent morning phototherapy with 10,000 lux of white light for 30-minutes experienced a reduction in depression and NES scores after 14 sessions.(43)
Another study by Pawlow et al. (2003) found that progressive muscle relaxation therapy (PMR) for stress, mood, hunger, and eating patterns has a positive effect on those suffering from NES. More specifically, researchers found that PMR can reduce the stress, anxiety, and salivary cortisol (the stress hormone) levels in those with NES immediately following therapy sessions. PMR also appears to boost hunger and reduce nighttime eating in those with the condition.(44)
Compared to other eating disorders, NES is less likely to lead to serious illness or disease. However, sleep disturbances in general can affect the quality of one’s life. Therefore, family members who suspect that a loved one is suffering from NES should broach the topic with the individual and suggest seeking treatment for it. In addition, nutritional education along with identifying triggers linked to night-time over-eating can play an important part in the recovery process. Lastly, referrals to specialists who are highly trained in the evaluation and treatment of eating disorders should be the first course of action in the treatment process.
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