Lack of Shut-Eye Leads to Supersized Kids, Study Says

Point the finger all you want at Ronald McDonald, but french fries and fast-food chains aren't the only things responsible for supersizing the nation's kids. Now, you can add skipping sleep to the list.

With America's growing obesity epidemic, experts are sleuthing for the culprit behind the staggering percent of overweight individuals, especially children. They've uncovered that a poor diet and lack of exercise are not the only contributors -- a lack of sleep is directly related to obesity and various problems with metabolism, according to a study published in Pediatrics.

When kids snooze, they lose -- or at least they don't gain weight, the report, which recommends children get 10 hours of sleep every night, shows. Young children who skimp on sleep have a four-fold risk of obesity compared to their more well-rested peers.

Researchers at Comer Children's Hospital at the University of Chicago Medical Center and the University of Louisville Birth Defects Center studied the sleep patterns and BMI (body mass index) of 308 children ages 4 to 10 for one week. The kids wore special wrist bands to track their sleep patterns.

Kids who got less sleep were more likely to have altered insulin, low-density lipoproteins and a high sensitivity to C-reactive protein plasma levels, according to the study.

Translation: Obese children had greater irregular sleep patterns on weekends than on school days and they tended to get less catch-up sleep compared with normal and overweight youngsters, ABC News reports.

Those who got the least amount of sleep overall had a 4.2 times higher risk of tipping the scales in the obese range than other children. When the researchers drew blood samples from a third of the children at random, the heaviest children also had the unhealthiest blood profiles.

Even children who slumbered little during the week but managed to make up for a small portion of missed sleep on the weekends tripled their risk of obesity, according to ABC News. This indicates that the children at the heaviest end of the weight range don't seem to be getting as much "catch-up sleep" on the weekends as children with lower BMIs.

"If a child has a tendency to be obese but gets adequate sleep, he is more likely to be protected than if he is not sleeping as much as he needs," Dr. David Gozal, a leading researcher of pediatric obesity and chair of the pediatrics department at the University of Chicago Medical Center, tells ABC News.

Prominent sleep researcher Dr. Phyllis C. Zee, director of the Sleep Disorders Center at Northwestern Memorial Hospital, tells ABC News there is growing evidence for a link between sleep duration and childhood obesity.

"What is new ... is that perhaps even more important than sleep duration is the effect of day-to-day variability of sleep-wake timing on weight regulation," she tells the network.

The researchers are calling for educational campaigns, aimed at families, promoting longer and more regular sleep for kids as one tool in the fight against childhood obesity.