Objectives: To test whether increased television viewing is associated with increased total energy intake and with increased consumption of foods commonly advertised on television, and to test whether increased consumption of these foods mediates the relationship between television viewing and total energy intake.
Design: Prospective observational study with baseline (fall 1995) and follow-up (spring 1997) measures of youth diet, physical activity, and television viewing. We used food advertising data to identify 6 food groups for study (sweet baked snacks, candy, fried potatoes, main courses commonly served as fast food, salty snacks, and sugar-sweetened beverages).
Setting and participants: Five public schools in 4 communities near Boston. The sample included 548 students (mean age at baseline, 11.70 years; 48.4% female; and 63.5% white).
Main outcome measures: Change in total energy intake and intake of foods commonly advertised on television from baseline to follow-up.
Results: After adjusting for baseline covariates, each hour increase in television viewing was associated with an additional 167 kcal/d (95% confidence interval, 136-198 kcal/d; P<.001) and with increases in the consumption of foods commonly advertised on television. Including changes in intakes of these foods in regression models provided evidence of their mediating role, diminishing or rendering nonsignificant the associations between change in television viewing and change in total energy intake.
Conclusions: Increases in television viewing are associated with increased calorie intake among youth. This association is mediated by increasing consumption of calorie-dense low-nutrient foods frequently advertised on television.