That's the surprising recommendation of a California study that suggests people who eat under the cover of darkness are more likely to overdo it.
A researcher gave questionnaires to 400 college students and discovered a link between bulimia -- an eating disorder characterized by bingeing and purging -- and dim lighting."If you are a dieter, you ought to pay more attention to things like the lighting level where you're eating," says study author Joseph A. Kasof, a psychology lecturer at the University of California at Irvine.
Kasof, who is in his 40s, became interested in bulimia and light exposure through his own experiences as an overeater two decades ago.
Although he was opposed to eating meat, he often gave into his urges for fast-food hamburgers after the sun went down.
"I discovered that, at night only, I would occasionally give in to these impulsive forces," he recalls. "I would have a 'Big Mac attack.' It was like I hadn't eaten meat in months."
Kasof never "ate like crazy" during daylight hours, and he wouldn't eat inside a brightly lit fast-food joint. Instead, he needed darkness.
"It reminded me of high school when I would take my girlfriend, pull down some street, and look for a dark area where we would park to perform our impulsive behaviors," he says.
Kasof recovered from his binge-eating problem, and began looking into whether bulimia sufferers are more prone to overeat in the dark.
He has published several studies on the topic. The latest appears in a recent issue of the journal Personality and Individual Differences, and focuses on three surveys of students at the University of California at Los Angeles, where he recently worked.
The studies found many bulimic or bulimia-prone students were more likely to prefer eating in dimness or darkness. The exception to the rule came among students who didn't express major concern about their weight.
In one survey, students were asked to disclose their preference for lighting during eating on a six-point scale, from one (very dark) to six (very bright). The average preference of the bulimic students was 4.28; that of the other students was 4.92.
The findings aren't as strange as they may seem, says Eric Stice, an assistant professor of psychology at the University of Texas at Austin who studies eating disorders.
Overeaters are sometimes divided into two groups -- those who try to resist temptation and those who don't, he says. Studies have suggested that people in the first category will slip into overeating behavior with only the slightest provocation.
"They're very easily set off," he says, even though they tend to worry a lot about their weight. A bad mood or alcohol consumption could spur them into overeating, and now it appears that dim lighting could make it easier for them to not notice how much they're eating, he adds.
"This doesn't suggest that we'd get fatter if we all replaced 80-watt bulbs with 20 watts," he says. "But those who are struggling with overeating would do better if they're not in dim environments."
What To Do
For more information on eating disorders, visit the National Eating Disorders Association.
To learn more about diagnosis and treatment, check out NOAH, the New York Online Access to Health.