High school kids who watched a lot more television than their peers at age 16 were likely to have worse eating habits five years later, a new University of Minnesota study indicates.
But this isn't to say that those who watched the least TV had nutritionally terrific eating habits, said study leader Daheia Barr-Anderson, an assistant professor in the University's School of Kinesiology.
"Children and adults in general aren't eating well," Barr-Anderson said. "There are lots of individual, social and environmental variables at work. But even though the intake of fruits and vegetables was suboptimal for all adolescents in the study to start with, they were even lower for those watching a lot of TV."
Barr-Anderson and her colleagues surveyed 1,366 Twin Cities-area adolescents on their TV viewing habits at the average age of 15.9 and then reviewed their eating habits five years later, when the average age was 20.5. The researchers divided them into three groups: limited viewers, who watched less than two hours a day; moderately high, two to five hours; and heavy viewers, at least five hours.
Five years later, there was a significant downward trend in the quality of diet as TV watching increased. For example, the total daily servings of fruits and vegetables ranged from 3.41 among limited viewers to 2.53 for heavy viewers.
In contrast, the U.S. departments of Agriculture and Health and Human Services recommend nine servings for a person consuming 2,000 calories a day (recommended servings rise and fall depending on caloric needs).
The intake of not-so-healthy foods ranged in the opposite direction: weekly visits to fast food outlets from 2.03 to 2.33, daily servings of snack foods from 1.93 to 2.20 and daily servings of sugar-sweetened beverages from 1.14 to 1.33.
The study could not identify the reason for a correlation between TV watching and future diet, but several possibilities exist. For one, some people may have a general disposition toward eating poorer diets and watching a lot of TV.
Or, embedded in the habit of watching television may be factors that steer adolescents toward lower-quality diets.
"Food advertising is a possibility. Repeated exposure to these [unhealthy] foods in ads may lead adolescents to consume more of them," Barr-Anderson said.
A second candidate is the tendency to eat while parked in front of the tube.
"Studies have shown that adolescents consume a lot of their caloric intake while watching TV," Barr-Anderson said. But in order to pinpoint a culprit, "there's a great need for more investigations."
Parents who want to guide their children toward healthier habits should – to the best of their ability – place firm caps on the amount of TV viewing and monitor what types of food the kids are eating, Barr-Anderson said, and that the American Academy of Pediatrics recommends only "quality" television for no more than two hours a day.
But parents also have to monitor themselves.
"I think kids see what their parents are doing," she said. "Until it becomes the norm in the family not to sit in front of the TV for hours or eat junk food, it's not going to change."
The study is published online in the Journal of Behavioral Nutrition and Physical Activity.