After years of concerns about American children’s continued weight gain, obesity rates among preschool-age children from poor families across the country have actually fallen for the first time in decades, The New York Times reported.

A new study from the Centers for Disease Control and Prevention (CDC) revealed that between 2008 and 2011, 19 states experienced a consistent pattern of decline in childhood obesity rates among low-income kids. In fact, the average obesity prevalence among low-income preschoolers is now one in seven, lower than the national average of one in eight.

“We are going in the right direction for the first time in a generation,” said Thomas R. Frieden, MD, director of the CDC. The agency based its study on the country’s largest database of health information about low-income children. Researchers used the weight and height measurements from 12 million preschoolers, ages 2 to 4, from across 40 states, who participated in federally funded nutrition programs.

After evaluating the data, researchers found that 18 states and the U.S. Virgin Islands experienced declines in preschool obesity rates. (Only three states reported increases.) In addition, 19 states showed no changes in childhood obesity rates. Compare that with 2009, when only nine states reported declines and 24 reported a jump in obesity among the youngest poor children.

Experts weren’t sure about the causes of the decline, but they’ve surmised that an increase in breast-feeding, a drop in sugary drink consumption and changes to food programs for women and children could be contributing to falling rates. Many parents interviewed during the study also said that during the last few years, they had become more educated about their families’ eating habits and the health problems associated with being overweight.

But scientists warn that there’s still much work to do to end the obesity epidemic. Researchers involved in the study said that most of the declines reported were modest, usually less than 1 percent. And among America’s minority communities, obesity rates are still much higher than the national average. One in five black preschoolers and one in six Latino youngsters are considered obese.

To help further combat obesity in school-age children, the federal government announced that it will ban all unhealthy snacks and sugary sports drinks from school cafeterias by 2014. For more information about the new dietary guidelines, click here.