Overdoing the late-night nosh

(This article was first printed in the March 2005 issue of the Harvard Health Letter. For more information or to order, please go to http://www.health.harvard.edu/health.)

Now and then many of us enjoy having a late-night snack. And remember Dagwood Bumstead’s midnight forays into the kitchen for one of his humongous sandwiches? But for some people, evening eating is no laughing matter. They’re trapped in a cycle of compulsive nighttime eating, a pattern labeled night eating syndrome (NES).

The causes are murky. Stress is often a trigger. Some research points to depression or hormonal imbalances. In small studies, people have been successfully treated with sertraline (Zoloft), an antidepressant, or topiramate (Topamax), an antiseizure medicine that is also used to prevent migraine headaches. Psychological strategies that break patterns of thinking or behavior that lead to night eating may also help.

Skipping breakfast

NES is on the radar screen because obesity is a hot topic, but it’s not new. Dr. Albert Stunkard, a psychiatrist at the University of Pennsylvania School of Medicine, and his colleagues first described it 50 years ago. Two classic features are lack of appetite in the morning (people with NES usually skip breakfast) and consumption of the majority of calories in the evening. A 1999 study in the Journal of the American Medical Association (JAMA) — still frequently cited — found that night eaters consumed 56% of their calories between 8 p.m. and 6 a.m., while a control group consumed only 15% during those hours.

Not all those with NES are overweight, but in many cases the problem is associated with severe obesity. Two studies published in the 1990s found that 25% of weight-loss surgery patients fit the NES profile. The syndrome may be one reason that some people have such a hard time dieting. Restricted eating during the day may stimulate even more eating at night.

A mixed bag

Overcoming Night Eating Syndrome, a book published in 2004, points out that the syndrome is difficult to classify because it combines elements of depression, an eating disorder, and a sleep disorder. Night eaters suffer from depression during the day, but they get even more depressed at night. They may gorge in the evening because food (particularly carbohydrates) has biological effects that lift their spirits — the familiar “sugar high” — and inhibit stress hormones. But it’s a temporary fix because out-of-control eating tends to feed a cycle of deflating guilt and self-recrimination, especially for a person who is trying to lose weight.

Night eating syndrome resembles binge eating. Both are triggered by stress. The eating in both has a compulsive quality and may cause deeply felt shame. But there are also important differences. Night eaters tend to snack; they usually don’t eat more than 400 calories at one time. Bingers may consume 2,000–3,000 calories in a sitting and don’t necessarily eat more at night.
In some respects, the sleep patterns of night eaters are normal. They tend to go to bed at a normal time, and most get up at a fairly normal time. But in other respects they have a disordered sleep — getting up two to four times a night and often having to eat in order to get back to sleep.

There’s also a small group of “sleepwalking” night eaters who aren’t conscious of what they’re doing. Nocturnal sleep-related eating disorder, as it is called, sometimes includes odd appetites — for a salt or sugar sandwich, for example, or even raw, frozen, or spoiled foods.

Hormonal abnormalities

Hormones govern our sleep cycles and appetites, so it’s not surprising that they might play a role in NES. Melatonin helps maintain sleep, and in most people, levels rise at night. The 1999 JAMA study found that people with NES had lower-than-normal levels of melatonin, which could explain why they get up so much. The appetite-suppressing hormone, leptin, also tends to peak at night, a pattern that may explain why most of us aren’t bothered by hunger as we sleep. The same JAMA study found that night eaters had low levels of leptin.

Treatment

There is no definitive treatment. Studies indicating that Zoloft or Topamax might help are small and preliminary.

Experts have found that making patients aware of the problem can help. Allan Geliebter, a research psychologist at Columbia, has described the case of a 25-year-old obese woman who wasn’t losing weight despite a super-low-calorie liquid diet. At first she denied having a problem, but then came to describe how, after nighttime trips to the bathroom, she’d sneak to the refrigerator to scoop up mouthfuls of pasta with her hands, so she wouldn’t leave dirty utensils behind as evidence. After she became aware of her problem, the solution was straightforward: Avoid food or drink three hours before bedtime. As a result, she didn’t need to go to the bathroom and was no longer tempted to eat pasta at night.

The authors of Overcoming Night Eating Syndrome, one of whom is Dr. Stunkard, take a similar approach. They encourage people with NES to learn about the condition and break the chain of nighttime eating behaviors by setting limits and recording thoughts in a journal. Because stress is a trigger, they recommend familiar stress-reduction techniques like deep-breathing exercises and progressive muscle relaxation.

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