Researchers analyzed data for four years in the city's schools. The findings are being reported in the journal Preventing Chronic Disease, but the authors are being cautious about what they think may be responsible for the drop.
The study says the prevalence of obesity decreased from 21.5 percent in 2006-2007 to 20.5 percent in 2009-2010. It also says the prevalence of severe obesity decreased from 8.5 percent to 7.9 percent.
The city, once labeled the fattest city in the country by Men's Fitness magazine, has taken numerous measures to cut down on childhood obesity. Those efforts include the removal of sugar-sweetened sodas from schools a few years ago.