By Elise Viebeck - 12/11/12 02:18 PM EST
New York City, Los Angeles and Philadelphia are seeing a slight decrease in their rates of childhood obesity, surprising researchers accustomed to decades of bad news on U.S. waistlines.
New York City reported a 5.5 percent decline in the number of children who are obese between 2007 and 2011, according to a new report, while Philadelphia and Los Angeles registered slightly smaller drops of 5 and 3 percent.
"It’s been nothing but bad news for 30 years, so the fact that we have any good news is a big story," New York City Health Commissioner Thomas Farley told The New York Times.
In Mississippi, for example, the number of obese children in kindergarten through fifth grade declined more than 13 percent between 2005 and 2011, according to RWJF.
Philadelphia's decline was seen as particularly heartening because it extended to ethnic minorities and low-income children, for whom obesity is a more persistent problem.
Experts attributed the drops to aggressive school nutrition policies that prohibit sugary drinks and enforce calorie limits.
These policies remain a matter of debate as the United States confronts its obesity crisis.
Opponents argue that setting standards and prohibiting the sale of certain foods in schools represents a "nanny state" approach to helping kids lose weight and violates free-market principles.