Banning junk foods at schools may help prevent childhood obesity
Washington: Banning sugary beverages and junk foods at schools may help prevent childhood obesity, according to a San Francisco State University study.
"This is one of the very first comprehensive investigations that examined whether childhood obesity trends changed after new statewide policies were enacted in California," said the study`s first author Emma Sanchez-Vaznaugh, assistant professor of health education at SF State.
Between 2003 and 2005, Governor Shwarzenegger signed SB 677, SB 965 and SB 12 into law, the first comprehensive set of statewide policies to eliminate sodas and other highly sweetened beverages and restrict the sale of junk foods in all of California`s public schools.
Although many other states subsequently enacted similar standards, potential effects on childhood obesity were uncertain.
Sanchez-Vaznaugh and colleagues used eight years of body mass index (BMI) data from fifth and seventh grade students collected as part of California`s annual Physical Fitnessgram testing.
The study compared BMI trends in the years preceding the enactment of the legislation with the years following the legislation. The data show that before the policies took effect, the rate of overweight students was increasing among all groups in the study (girls and boys in fifth and seventh grades).
However, in the three year period after the policies became effective, the increase in the number of overweight children was significantly reduced among fifth-grade boys and seventh-grade students of both sexes throughout California. The pre- and post-policy trends in overweight were not significantly different among fifth-grade girls.
The researchers also looked at children in the Los Angeles Unified School District (LAUSD) separately, because the district passed slightly stricter, but otherwise similar policies in their district the year before the passage of California`s SB 677.
Prior to the implementation of the policy there was an upward trend of overweight fifth and seventh-grade students in the Los Angeles area.
When the researchers compared these trends in the period after the new policies were implemented, they found that the increasing trend in the number of overweight fifth-grade students in the Los Angeles significantly slowed.
There were no significant changes among seventh-grade students in Los Angeles.
"Although policymakers cannot directly influence student behaviour, our study shows that governmental policies can help define the environment in which children learn to make food choices and thus shape the food behaviours, influencing overweight trends in entire student populations," Sanchez-Vaznaugh said.
The study has been published in the March issue of the journal Health Affairs.