Serious TV Watching May Increase BMI in Teens
Previous studies suggest that the amount of screen time spent by teenagers is associated with body mass index (BMI, a measure of body fat). David Bickham, PhD, of Harvard in Boston, and colleagues report in a new study, however, that it may not be the amount of time spent that influences body weight, but rather, the attention they pay to TV watching that may be more significant.
The results of the study, which was published in Pediatrics reveal that adolescents who paid the highest levels of attention to watching TV had more than 2 points higher BMIs than those who did not pay too much attention to it. The authors point out that that the association between BMI and screen media time was not found across other forms of media such as computers and video games.
The authors believe that advertising of unhealthy foods and drinks through television may be the mechanism, which influences BMI increases. They note that among the different forms of screen media, it is only TV that consistently conveys food advertising, especially those that endorse energy-dense, less nutritious foods.
The study involved self-assessment reports from 91 adolescents aged 13-15 years from a small city in New England. Data collection included the teens’ recall estimates, diaries, ecological momentary assessment (EMA), and BMIs. Participants were asked to complete a week-long self assessment of how they used various forms of screen media including video games, computer, music, phone, or TV/movies. They used 24-hour diaries on a random weekday and Saturday, which were validated by repeating the process for another week and day. Participants were also asked about their physical activity.
The authors believe that the increase in BMI of teens who paid much attention to TV could be the result of the distraction provided by TV which leads to “unconscious eating” that makes them less aware of physiological hunger and satiety signals. They note that teens generally eat energy-dense snack foods and are less aware of the amount they are eating.
Petrochko, C. Being Engrossed by TV May Boost Teens’ BMI. MedPage Today.