Sleep Loss Feeds Appetite
Mixed-Up Hormones Lead to Munchies, Bigger Waistlines
Sleep Loss Affects Cravings
In the second study, 12 healthy males in their 20s were studied to see how
sleep loss affected both leptin and ghrelin levels. The young men got only four
hours of sleep for two nights, then two nights of 10 hours in bed (average of 9
hours of sleep). Hormone levels were measured before, during, and after the
sleep periods. They also completed questionnaires to assess their hunger and
desire for different foods.
After a night of four hours of sleep, sleep restriction resulted in a 24%
increase in hunger and a 23% increase in appetite, reports study co-researcher
Esra Tasali, MD, a sleep specialist at the University of Chicago Medical
Center. "If allowed to increase their food intake, they would likely eat an
extra 550 calories a day," Tasali tells WebMD, whose study appears in
Annals of Internal Medicine.
As the sleepy guys got hungry, their food choices also changed. High
calorie, high-carb foods were most appealing -- sweets, and salty and starchy
foods -- after two nights of little sleep. Fruit, vegetables, and dairy
products were at the low end of the craving scale.
"For normal, healthy, sedentary adults, that would result in significant
weight gain," she says. "Of course, under laboratory conditions, they
didn't have free access to food. But in real life, sleep restriction may be a
previously unrecognized risk factor for this epidemic of obesity."
Today's sleep loss studies are "a good indicator of which way
investigation should proceed," Satya P. Kalra, MD, professor of
neuroscience at the University of Florida in Gainesville, tells WebMD.
"It's growing evidence that if you're sleep deprived, there's a human
tendency to eat more -- although that hasn't yet been measured," Kalra
These studies of sleep loss "are very well controlled," Kalra says.
"They show we're on the right track."