The rate of obesity among young US children is declining, according a new study in the Journal of the American Medical Association.

For the 2- to 5-year-old age group obesity rates have declined 43 percent, the study found.

Between 2003-2004 the obesity rate for this age group was 14 percent, but it dropped to 8 percent in 2011-2012, according to data from the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES).

"We continue to see signs that, for some children in this country, the scales are tipping. This report comes on the heels of previous CDC data that found a significant decline in obesity prevalence among low-income children aged 2 to 4 years participating in federal nutrition programs," said CDC Director Tom Frieden. "We've also seen signs from communities around the country with obesity prevention programs including Anchorage, Alaska, Philadelphia, New York City and King County, Washington. This confirms that at least for kids, we can turn the tide and begin to reverse the obesity epidemic."

The reasons for the decline in childhood obesity between the two survey periods are unclear, but over the past few years many child care centers have started to improve their nutrition and physical activity standards, which may be a reason for the decline in early childhood obesity, the researchers said.

The NHANES data also indicated a decline in the number of sugar-sweetened beverages among youth in recent years, which could play a role in the decline.

In a statement from the CDC, Michelle Obama, First Lady of the United States of America credited her Let's Move! program with some of the success.

"I am thrilled at the progress we've made over the last few years in obesity rates among our youngest Americans," she said. "With the participation of kids, parents, and communities in Let's Move! these last four years, healthier habits are beginning to become the new norm."