School Lunches, TV Time Linked to Childhood Obesity

ANN ARBOR, Mich.Childhood obesity links to behaviors such as school lunch consumption and watching TV for two hours or more per day, according to new findings that will be published in the September issue of Pediatrics.

Researchers from the University of Michigan Frankel Cardiovascular Center examined habits that can lead to obesity and future heart risk using data from 1,714 sixth grade students involved in Project Health Schools. Students enrolled in sixth grade at 20 schools in Detroit, Ann Arbor, Ypsilanti and Owosso were eligible for participation in this study. The median age was 11 years.

While some habits stayed consistent for all overweight and obese children, the study found some gender differences in the habits influencing body weight. Girls who drank two servings of milk each day were less likely to be obese, and boys who played on a sports team were at a healthier weight.

Also, 61% of obese boys and 63% of obese girls reported watching television for two or more hours a day. The assumption is watching television mediates physical activity, but there were gender differences in how children spent their screen time.

When asked, obese girls were more likely than any other group to use a computer. Obese boys reported playing video games more often than normal weight boys, although the association was not as strong as in other studies.

We did not find a significant association between time spent playing video games and obesity among boys, which has been observed in other studies," said the study's lead author Morgen Govindan, an investigator with the Michigan Cardiovascular Research and Reporting Program at the University of Michigan. Although we saw a similar trend, the association was not as strong, perhaps due to our smaller sample size."

She added that exploring gender-related differences in a larger group may help refine the interventions to promote weight loss and prevent obesity among middle school children.

Obese boys and girls had poor cardiovascular profiles with lower HDL-cholesterol levels, higher triglycerides, higher blood pressure and higher heart rate recoveryindicating a lower level of fitnesscompared to kids at a normal weight.

Milk consumption seemed to protect girls from obesity, but made no difference for boys. A possible explanation would be a reduction in sugary drinks, which girls replaced with milk. Recent research shows these sweetened drinks can add on extra pounds when consumed by young children.

Although we were not able to examine the specific nutritional content of school lunches, previous research suggests school lunches include nutrient-poor and calorie-rich foods," said cardiologist and senior study author Elizabeth Jackson, M.D., M.P.H., assistant professor of internal medicine at the University of Michigan Medical School.

Other studies have linked eating school lunch with obesity, but a major issue with such studies, Jackson said, is the influence of socioeconomic status. Poor children eligible for free or reduced school lunch may already be overweight, considering the link between obesity and lower socioeconomic status. Luckily, research shows obesity in low-income students declined 19% from 2008 to 2011.

 Additional work is needed to help us understand the beneficial impact of improving school lunches and decreasing screen time," Jackson said. Presumably, playing video games or watching TV replaces physical activity."

Public health policy changes, such as limits on access to sugary drinks in schools, could help  reduce the increasing obesity rates in school children. In addition, studies show increasing the price of a calorie by 10% could help lower the percentage of body fat in children, while an increase in fast food prices may also improve obesity outcomes.