Junk Food, TV-Watching Linked Among Teens

One of the key findings was that "TV-watching is associated with unhealthier eating patterns, even when you control for eating while watching TV," said study researcher Ronald Iannotti, of the National Institute of Child Health and Human Development.

In other words, watching television affects what kids eat, well beyond the time they are actually parked in front of the tube.

Television-watching among children has previously been linked with eating more junk food and less fruits and vegetables, but the new study is the first national, large sample of teens in the U.S. The results are consistent with previous smaller studies, said Stuart Biddle, executive director of the British Heart Foundation National Centre for Physical Activity & Health, who was not involved with the study.

TV and eating habits among students

Not eating enough healthy, nutritious foods, and instead consuming sugary and high-salt foods raises the risk of obesity and chronic disease later in life.

The new study included 12,642 students from across the country in fifth through tenth grades, taking part in the Health Behavior in School-Aged Children Study, which is conducted every four years. Eating habits varied along age, gender and racial lines. According to the study, younger students were more likely to eat fruits and vegetables than older students, girls were more likely to eat them than boys, and white students were more likely to eat them compared with black and Hispanic students.

Fast-food consumption was more frequent among nonwhite students and older students, but equal for both boys and girls.

On average, students watched an estimated 2.4 hours of television per day, and devoted 2.8 hours a day to computer time, similar to previous studies. The American Academy of Pediatrics recommends limiting all screen time to less than two hours per day.

Vigorous physical activity was lower than previous reports. It was also lower for girls compared with boys (by about 0.4 hours per week), and higher for white students compared with other ethnic groups. The students who ate more fruits and vegetables, rather than candy, soda, and fast food were more likely to engage in weekly physical activity.

Because unhealthy eating habits can continue into adulthood and lead to a sedentary lifestyle, large studies that identify factors contributing to unhealthy behaviors can help establish programs to improve kids' health. "One strength of [this study] is that it allows analyses by ethnic groups, and these show differences. This suggests that some groups may benefit more from interventions over others, "Biddle said.

What parents and kids can do

Biddle said children and adolescents should not eat meals or snack in front of the TV. The experts suggested that parents prepare lots of cut-up fruit and make it available in the TV area, and avoid or reduce buying high-sugar drinks and high-calorie snack food.

"If junk food is in the house, it will be eaten. Parents should discuss alternatives to sugary and high-calorie snack food with their kids," Biddle said.

Parents should also encourage kids and teens to eat breakfast, he said. "Those who skip breakfast are more overweight or obese and less healthy in general," said professor Jean-Philippe Chaput, of the Healthy Active Living and Obesity Research Group at the University of Ottawa.

The study showed an association between television and eating junk food, and while there could be a cause-and-effect relationship at work, it could also be that both watching television and eating unhealthy foods are generally more likely to occur in the same households. Such households, Biddle said, may also be more likely to take part in unhealthy habits such as smoking and would be less likely to participate in sports.

Future studies need to look at how to reduce screen-related activities in kids and teens. "I think that it will be a Herculean task, because kids and adults are addicted to the screen, and it is becoming omnipresent in our daily life," Chaput said.

"TV-viewing has been shown to stimulate food intake regardless of appetite. It is worse than doing nothing, sleeping or napping for example, because it creates a positive caloric balance," Chaput said.

"It is one thing to show that TV or computer use is bad for our health, but it doesn't mean that people will be giving up their screens because of that," he said.

The studyis published today (May 7) in the journal Archives of Pediatrics & Adolescent Medicine.

Pass it on: Students who watch more television are more likely to have unhealthier eating habits, substituting fruits and vegetables for sweets, soda and other junk food.