Sleep Loss Feeds Appetite
Mixed-Up Hormones Lead to Munchies, Bigger Waistlines
Dec. 6, 2004 - America's hectic lifestyle, fueled by sleep loss, is feeding
the obesity epidemic, according to new research.
This week, two studies address this phenomenon -- building on earlier
research pointing to the same conclusion - that sleep loss "brings about
physiologic changes in the hormonal signals that promote hunger and, perhaps
thereby, obesity," writes Jeffrey S. Flier, MD, with Beth Israel Deaconess
Medical Center in Boston, in his editorial in Annals in Internal
The "simple goals" to get a better night's sleep and more exercise
"may well become a part of our future approach to combating obesity,"
But sleep loss is just one factor in weight control, senior researcher
Emmanuel Mignot, with the Howard Hughes Medical Institute at Stanford
University, tells WebMD.
"It's certainly not the only factor. It's not that sleeping two or three
more hours will solve a weight problem. It's one of many factors, and a factor
that no one has looked at very much. It's good that sleep loss is getting so
much attention right now. It's amazing what we're discovering." Mignot
co-authored a study appearing in the journal Public Library of
The Evidence Against Sleep Loss
Just last month, another study came to similar conclusions -- that chronic
sleep loss triggers hormones that can lower the "appetite control"
hormone leptin. Lower levels of leptin are associated with obesity. It's what
researchers call the "yin yang" of appetite control. The hormone
ghrelin is produced in the stomach and triggers hunger. Leptin is produced by
fat cells and signals satiety, telling the brain when we have eaten enough.
Mignot's study investigated the effects of sleep loss on body mass index
(BMI), an indirect measure of body fat. His was part of an ongoing sleep
disorder study involving 1,024 Wisconsin state employees, all between 30 and 60
For researchers, this type of large-scale, ongoing study "is a good way
to show that what you are finding applies to the general population,"
Mignot tells WebMD.
Every four years, each volunteer came to a sleep laboratory for an overnight
stay, with blood sampling and a check of BMI and weight. Every five years, each
completed a questionnaire about sleep habits; they also kept a six-day
During the 15-year study period (since 1989) researchers found that short
sleep was associated with low leptin levels. They show a 15% increase in
ghrelin and a 16% decrease in leptin in people who consistently got only five
hours of sleep.
"It shows that there is a regulatory problem," Mignot tells WebMD.
"In natural evolution, when you were more active, you needed to eat more
calories, so you had this natural reaction that increased your appetite and
your sleep." Compare that with today, when people aren't as physically
active yet burning the candle at both ends, either in traffic or in front of
the TV. Also, food is more readily available. All those factors have caused
increase in weight.
Researchers also show an association between sleep duration and BMI. Those
getting three hours of sleep had a 5% increase in body weight. "That's not
an enormous amount, but the effect might be underestimated," says Mignot.
"Still, it's something we can do something about. It may be the reason why
dieting has been so disappointing for so many people."