By reducing children's and youth's TV viewing time, it has been shown that junk food and SSB consumption decrease. Food choices throughout the day are mitigated by a reduction in exposure to advertising of food and beverages on TV. Based on a 2009 study conducted by the Kaiser Family Foundation, children and youth ages 8 to 18 years spent on average 2 hours and 39 minutes watching live television on a typical day. Total video game time (on a console player, cell phone, or handheld player) was on average 1 hour and 13 minutes.
Using regression models, Sonneville and Gortmaker (2008) estimate that every 1 hour increase in watching TV was associated with a 105.5 kcal increase in total energy intake. Each hour of playing video and computer games is associated with an increase of 91.8 kcal per hour. The model uses Metabolic Equivalent of Task (MET) values for boys ages 13 to 15 and girls ages 12 to 14 as the basis for calculating calories expended. Differences in males versus females may exist, but the study was underpowered to detect significant differences.
Sonneville and Gortmaker estimate the total energy intake and the energy gap associated with behaviors of adolescents during leisure behaviors, including sports, chores, TV viewing, and reading or doing homework. Based upon a prospective study design, 538 students from Boston-area public schools were studied from fall 1995 to spring 1997. Anthropometric and dietary assessments were collected, along with measures of TV, video, reading/doing homework, and physical activity.
Mean baselines collected include: 48.46 kg, 20.71 BMI, 2139.19 kcal per day consumption, 3.31 hours per day of TV watching, 0.89 hours per day of video and computer game playing, 1.55 hours per day of reading and/or doing homework, and 1.33 hours per day of moderate-to-vigorous physical activity.
Mean follow-up data collected include: 57.50 kg, 22.23 BMI, 2293.98 kcal per day consumption, 3.10 hours per day of TV watching, 0.77 hours per day of video and computer game playing, 1.35 hours per day of reading and/or doing homework, and 1.27 hours per day of moderate-to-vigorous physical activity.
Guran and Bereket (2011) describe the mechanisms by which TV viewing time may affect or displace time spent engaging in physical activity. The additional time spent in media intake and exposure may also have the added affect of shaping food choices and caloric intake throughout the day.
For the calculations, a MET value of 1.34 kcal per kg per hour was used as reported by Harrell et al., which is the estimated resting energy expenditure value for boys aged 13-15 years and girls ages 12-14.
* The Average Caloric Impact (ACI) for this intervention is empirical, based on trial data from Sonneville and Gortmaker (2008). Epstein et al. (2008) and Miller et al. (2008) report similar impacts.
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