According to foodconsumer.org, previous studies have already associated childhood overweight with television viewing, but the common perception is that the link between childhood overweight and TV viewing is due to children's physical inactivity associated with television viewing.
Children who spent more time watching TV were more likely to eat more of the calorie-dense, low nutrient foods advertised on television, indicating that the junk food ads play a role in the ever-increasing trend of childhood obesity.
The study provides evidence that television is effective in getting kids to eat the foods that are advertised, and this drives up their total calorie intake.
For the study, 548 students in sixth and seventh grade in Boston were surveyed for their dietary patterns including use of the snacks and beverages such as soda, chips, fast food and baked snacks like cookies, which are commonly advertised on television, and their television viewing habits including the number of hours spent watching television each day of the week. They did the survey again19 months later.
Longer television viewing was associated with higher intake of calories, one hour television viewing increasing consumption of 167 calories - just about the amount of calories in a soda or a handful of snack food.
In addition, each additional hour of television viewing was independently linked with increased consumption of foods commonly advertised on television, which were shown to be responsible for much of the calorie increase, according to the study. The association between viewing time and sugar-sweetened beverages was the strongest.
Compared to their counterparts growing up 20 years ago, children and teens today are twice and three times more likely to be overweight, respectively. Childhood overweight increases their risk of developing obesity and obesity-associated diseases such as diabetes and heart disease in their adulthood.
Experts recommend that children's watching television should be limited to less than two hours a day to both lessen sedentary time, a risk factor for childhood overweight, and reduce exposure to content associated with negative consequences. The result of the current study reinforces the necessity of this limit.