A new study has linked school lunch consumption and two hours or more of daily TV viewing to obesity in middle-school children.
While some habits were the same for all overweight and obese children, the study found some gender differences in the habits influencing body weight.
Data from 1,714 sixth grade students enrolled in Project Healthy Schools showed girls who drank two servings of milk each day were less likely to be obese, and boys who played on a sports team were also at a healthier weight.
"Additional work is needed to help us understand the beneficial impact of improving school lunches and decreasing screen time," cardiologist and senior study author Elizabeth Jackson, M.D., M.P.H., assistant professor of internal medicine at the University of Michigan Medical School, said.
"Presumably playing video games, or watching TV replaces physical activity," she said.
Students enrolled in sixth grade at 20 schools in the southeastern Michigan communinities of Detroit, Ann Arbor, Ypsilanti and Owosso were eligible for participation in this study. The median age was 11.
Obese boys and girls had poor cardiovascular profiles with lower HDL-cholesterol, higher triglycerides, higher blood pressure and higher heart rate recovery - indicating a lower level of fitness - compared to normal weight kids.
"Cardiovascular disease doesn't just start in adulthood, and there may be factors that could help us identify during youth or adolescence who might be at increased risk for developing health problems later on," Jackson said.
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.
"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," Jackson said.
The findings are set to be published in the journal Pediatrics.
