WEDNESDAY, Sept. 1 (HealthDay News) -- Teens who sleep less than
eight hours a night are more likely to eat a high-fat diet that
puts them at risk for obesity and the many health problems
connected with it, new research shows.
The study, published in the Sept. 1 issue of the journal
Sleep, found that these sleep-deprived teens consumed 2.2 percent more calories from fat, and ate more snacks than those who slept eight hours or more a night. They also ate more total calories.
"There's been a lot of research over the last five years implicating insufficient sleep with obesity," said study author Dr. Susan Redline, of Brigham and Women's Hospital and Beth Israel Deaconess Medical Center in Boston.
"Some experimental studies on sleep deprivation in controlled laboratory environments show a craving for fatty foods among the participants" who got less sleep, she said.
Redline, a professor of medicine with the school's division of
sleep medicine, said sleep-deprived teens may suffer from metabolic
disturbances that have been linked to obesity and insulin
resistance in other research with shift workers whose sleep was
Metabolism is the body's process for turning calories into
energy. Lack of sleep can affect metabolism by changing the level
of appetite-regulating hormones like leptin and ghrelin, setting
the stage for poor eating habits, Redline explained.
In addition to being a possible cause of metabolic problems,
fewer hours of sleep provided teens with "more opportunities to
eat," Redline said.
Teens need about nine hours of sleep every night to feel rested
and alert the next day, but few teens get that amount, experts
"I almost never see anyone who is sleeping more than seven hours a night," said Dr. Paula Elbirt, an associate professor of pediatrics and adolescent medicine at Mount Sinai Medical Center in New York City. Insufficient sleep among teens is "the rule, not the exception," she said.
Elbirt said the "adolescent lifestyle" encourages teens to stay
up late. Socializing on cell phones and computers, playing video
games and watching television keep teens awake into the middle of
the night, she said, noting that daily stress may be an underlying
reason for staying up late.
Elbirt said that while the "prevailing view is that a calorie is
a calorie," there is some evidence that calories from fat are more
likely to be metabolized into more stored fat. Also, the more fat
you eat, the more you crave, she said.
Teens are also "phase-delayed" according to the study, meaning
that their circadian rhythm is shifted in a way that makes them
alert at night and sleepy in the morning, eating into the night
And because school starts early for most teens, they tend not to
get the sleep they need, experts said.
"All of us have a clock system inside us and it keeps 24-hour time," said Dr. Kenneth P. Wright Jr., an associate professor of integrative physiology at the University of Colorado in Boulder. "In adolescence, this system changes, and it drives a lot of our behaviors, like when we sleep."
Wright, at the school's Center for Neuroscience, likened
adolescents to people "on the East Coast, living on a West Coast
The study measured the hours slept of 240 teens for five to
seven consecutive 24-hour periods on weekdays. The teens wore wrist
meters measuring their movements to determine wakefulness and
sleep. They were interviewed twice within 24 hours of eating about
what foods they ate, the amount they ate, and when and where.
Teens who slept less than eight hours a night consumed, on
average, 1,968 calories a day. Those who slept eight hours or more
averaged 1,723 calories a day. The teens slept a little less than
an average of eight hours a night. Only 34 percent of the
participants slept eight hours or more.
Wright cited the study's "strong methodology," calling it a
"step forward" in examining the relationship between lack of sleep
"When we think of adolescents and lack of sleep, we think of drowsy driving, and learning is impaired, but this study also shows that there are real health consequences for teens," said Wright. "It supports the notion that sleep is important for our health."
For more information on sleep and teens, go to the
National Sleep Foundation.