The debate about the impact of TV violence continues (see Research Watch, Feb. 2001), but there is growing evidence that TV viewing contributes to children's obesity, which is on the rise among youth of all ages.
This very solid study of more than 4,000 boys and girls between eight and 16 finds that obesity is twice as likely among kids who watch four or more hours of TV per day (16 percent) as it is among those watching one hour or less per day (8 percent).
Kids who watch more TV probably have less time for physical activity, but that does not seem to be the reason for this link between TV and obesity.
The study was based on the NHANES III, a survey conducted by the U.S. Centers for Disease Control and Prevention, which included a home interview and medical examination of a nationally representative sample of children and adults. The study focused on the three largest ethnic groups in the U.S.: Non-Hispanic whites, African Americans and Mexican Americans (not including other Hispanics).
Kids who watch more TV probably have less time for physical activity, but that does not seem to be the reason for this link between TV and obesity. Surprisingly, there was no evidence that vigorous physical activity prevented obesity. However, kids (especially girls) who watched more TV tended to consume more calories. How much TV do these kids watch? Almost half watched more than two hours a day, and the boys watch more TV than the girls. Most African-American and Mexican-American children watched more than three hours per day, compared to 37 percent of non-Hispanic white kids. Blacks were the heaviest TV viewers: 17 percent watched five or more hours each day, compared to 9 percent of Mexican Americans and 6 percent of whites.
Boys were more physically active than girls, on the average, and white boys were most likely to participate in physical activity at least five days each week (72 percent), and African-American girls were least likely to do so (42 percent).
TV viewing was related to obesity even when other potentially important factors were statistically controlled: Girls who watched more television were more likely to be obese, regardless of their weekly physical activity, energy intake, age, race/ethnicity and family income. This was not true for boys.
The study did not evaluate how much time the children spent in front of a computer. However, the data were collected between 1988 and 1994, before computers were as popular among children as they are today. It is possible that the popularity of computers has led to a decrease in TV viewing.
Since watching TV, eating and playing sports are major components of most children's daily lives, this study has important implications for youth workers. How often are TV programs, videos, and films used as part of recreation programs, daycare and after-school programs, and even school programs and homework assignments? In contrast, how often do youth workers encourage youth, or their parents, to spend less time in front of the TV or to avoid eating while watching TV? This study suggests that youth workers can help kids by being more aware of how sitting (and eating) in front of the TV contributes to obesity, and by encouraging alternative activities.