According to the U.S. Centers for Disease Control and Prevention, more than one in six children and teenagers are obese -- up three-fold from a generation ago.

While experts agree there are several reasons for this development, they are increasingly focusing on the role of excess "screen time" -- both for its physical effects on kids and the advertising messages that TVs and computers are delivering to them.

Last April, four government agencies requested public comments on a set of voluntary principles for marketing food to children, with the Federal Trade Commission calling childhood obesity "the most serious health crisis facing today's youth." However, voluntary guidelines will not cut it, according to the AAP.

Nearly a third of American youngsters eat fast food on any given day, the AAP says, with the nation spending in excess of $110 billion every year on things like burgers and French fries -- "more than that spent on higher education, computers, or cars."

In 2009, the fast food industry spent $4.2 billion on ads in various media, and research shows they work. For instance, one study found kids watching cartoons downed 45% more snacks when they were exposed to food ads instead of ads for other products.

The National Restaurant Association did not return a request for comment in time for this story.

Sitting glued to the TV or the computer for hours on end also eats up time that could have been used for physical activities, said Strasburger, and studies have tied certain screen habits to sleep problems.

"I think parents have always thought that if their kids were in their room watching TV or on the Internet, they were happy and safe," he added. "The research says, maybe not."

In one new report, also published in Pediatrics, preschoolers who had a TV in their bedroom took longer to fall asleep and were drowsier during the day.

Among kids who spent more than 30 minutes playing video games, watching TV or surfing the Web in the hour before they went to bed, 28% had sleep trouble, compared to 19% of those who had less or no screen time.

Violent content also tended to keep kids up at night, no matter when they watched it.

While the study could not tease out cause and effect, Michelle Garrison, who led the research, said the evidence hints screen may be responsible for at least part of the problem.

"One thing that families can take away from this is to focus on day-time, non-violent media choices," Garrison, of Seattle Children's Research Institute, told Reuters Health.

She added that sleep problems can take a toll on daytime wellbeing.

"We see increased behavior problems, we see increased learning problems, and excess weight and obesity," Garrison said.

Experts say parents should play an active role in managing their kids' screen time.

"Parents should serve as positive role models for their children and limit their own as well as their child(rens')s television viewing," said Dayna M. Maniccia, of the University at Albany in New York.

In a new study, also in Pediatrics, Maniccia and her colleagues found using an electronic device to ensure the TV turns off at a certain time also appears to be effective.

"Limiting advertisements would be a positive step toward improving children's health," Maniccia added in an email to Reuters Health. "Young children can't distinguish between ads and programs."

Several companies have already pledged to shift their advertising toward healthier choices for young kids, yet research from last year shows fast food restaurants are stepping up marketing directed at children and toddlers.

"It's all just a smokescreen anyway -- the big fast food corporations are basically interested in making money, not making good nutritional products," said Strasburger. "With billions of dollars in profits every year should come a sense of public health responsibility. Unfortunately, it doesn't seem to."

McDonald's, which targets kids in much of its advertising, declined to comment.

In the meantime, Strasburger urges families to follow a few simple steps.

"Parents need to listen to the AAP guidelines which say, 'Limit your child to less than two hours of media time per day, keep the TV set and Internet out of the bedroom and avoid screen time in kids under two.'"

However, cutting screen time alone is not enough, according to Strasburger.

"We have to give kids healthy alternatives to being couch potatoes," he said. "The question is, how fat do we want people to become? Congress needs to think about that."

From the June 27, 2011, Prepared Foods' Daily News.