After three decades of increases, adult obesity rates held steady in the past year in virtually all 50 US states, according to an annual report released Friday.

Arkansas was the lone exception to a trend that offers a glimmer of hope that Americans might finally be turning the corner in their long-term struggle against excess weight.

Thirteen states now have adult in excess of 30 percent, with Louisiana (34.7 percent), Mississippi (34.6 percent) and Arkansas (34.5 percent) topping the list.

Colorado at 20.5 percent had the lowest obesity rate—still a sobering figure when, in 1980, no state at all had a rate surpassing 15 percent.

The data appears in "F as in Fat: How Obesity Threatens America's Future," produced by the non-profit Trust for America's Health and the Robert Wood Johnson Foundation.

"While stable rates of may signal prevention efforts are starting to yield some results, the rates remain extremely high," said Jeffrey Levi, executive director of the trust, a group.

Even if current rates hold steady, with obesity-related illnesses—and a fast-rising number of extremely obese Americans—will weigh heavily on the nation's , he said in a statement.

Obesity was generally highest in the South and Midwest, among those who did not complete high school, and those earning less than $25,000 a year, according to the report.

Earlier this month, fresh data from the Centers for Disease Control revealed a slight decline in obesity among low-income preschoolers for the first time in decades.

On the web: www.healthyamericans.org