Competitive food sales in schools and childhood obesity: A longitudinal study.
Author Interview: Jennifer Van Hook and Claire E. Altman
Jennifer Van Hook
Director, Population Research Institute
Professor of Sociology & Demography
601 Oswald Tower
University Park, PA 16802
What are the main findings of the study?
We find that weight gain has nothing to do with the candy, soda, chips, and other junk food middle school students can purchase at school. The research relies on data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999, which follows a nationally representative sample of students from the fall of kindergarten through the spring of eighth grade. We used a subsample of 19,450 children who attended school in the same county in both fifth and eighth grades.
We found that 59.2 percent of fifth graders and 86.3 percent of eighth graders in our study attended schools that sold junk food. But, while there was a significant increase in the percentage of students who attended schools that sold junk food between fifth and eighth grades, there was no rise in the percentage of students who were overweight or obese. In fact, despite the increased availability of junk food, the percentage of students who were overweight or obese actually decreased slightly from fifth grade to eighth grade.
Were any of the findings unexpected?
Yes, our findings seem to defy common sense. After all, we all know that children who eat junk food and soda are more likely to gain weight. But to understand what is going on, we need to take into consideration all of the places where children eat. Schools only represent a small portion of children’s food environment. Children can get food at home and their neighborhoods, and many children can walk down the street from the school to buy food. Additionally, children are actually very busy at school, so there isn’t much opportunity for them to eat while they’re in school, or at least snack endlessly, compared to when they’re at home. School days are scheduled from beginning to end, including time spent eating. This differs considerably from home environments, where mealtimes are less regular, eating blends with other activities such as TV viewing, opportunities for snacking are greater, and food consumption is less closely monitored, especially for children staying home alone.
What should clinicians and parents take away from this study?
Obesity is a significant health issue facing children today. The percentage of obese children tripled between the early 1970s to the late 2000s. Diet and physical activity play an important role in obesity. However, childhood obesity cannot be placed solely in the hands of a single institution such as schools. Instead, to combat childhood obesity a coordinated response among educators, health care workers, parents, businesses, and government is probably required. This message may come as a disappointment to those hoping for an easy solution.
Additionally, this study suggests that we need to think more holistically about children’s’ food environments. Food is ubiquitous so the elimination of junk food sales in schools is unlikely to make much of a dent in the child obesity epidemic.
What recommendations do you have for future research as a result of your study?
Future research needs to take into account children’s development. Children’s food preferences and eating habits are firmly established early in life, so middle school environment may not matter much. Early childhood experiences and home environments have profound effects on children’s dietary patterns. For example, some research suggests that children can lose the ability to self-regulate food consumption (and stop eating when full) in early childhood, largely as a consequence of child feeding practices. This suggests that when it comes to combating childhood obesity and weight issues, researchers should put more emphasis on younger children.
Competitive Food Sales in Schools and Childhood Obesity: A Longitudinal StudyJennifer Van Hook and Claire E. Altman
Sociology of Education, January 2012;
vol. 85, 1: pp. 23-39., first published on August 8, 2011