(HealthDay)—The 2009 changes to the U.S. Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) was associated with a change in the trend of obesity prevalence among 2- to 4-year-old children, according to a study published online April 1 in Pediatrics.

Madeleine I.G. Daepp, from the Massachusetts Institute of Technology in Cambridge, and colleagues examined the correlation between the 2009 changes to the WIC food package and childhood obesity trends. State-specific was examined among WIC-participating 2- to 4-year-old from 2000 to 2014. The in obesity prevalence was estimated for states before and after the WIC package revision.

The researchers found that the prevalence of obesity across states was increasing 0.23 percentage points annually among 2- to 4-year-olds before the 2009 WIC food package change. The trend was reversed after 2009 (−0.34 percentage points per year). The change in the trend in obesity prevalence was not explained by sociodemographic changes and other obesity risk factors.

"A change in the trend in prevalence related to dietary changes resulting from the 2009 package change is plausible," the authors write. "A substantial body of evidence has shown that the dietary habits of WIC participants improved from before to after the package change."