South Dakotans have been cutting down on smoking and binge drinking but not on calories.

One study shows the state has gone from the 13th-least obese state to the 29th least obese.

"It's not something that's surprising to us," state Secretary of Health Doneen Hollingsworth said. "It's an area we are focusing increased programming and resources on."

The 2008 America's Health Rankings shows that the percentage of South Dakotans who smoke has decreased from 28.6 to 19.8 over the past 18 years. The percentage of people who binge drink is down from an estimated 20.4 percent in 2003 to 17.7 percent over the same period.

But obesity rates have increased. Just 10.7 percent of South Dakotans were obese in 1990, the rankings say, but the figure has increased to 27.2 percent this year.

Hollingsworth said the Health Department is focusing many of its fat-busting efforts on children, because she said leading children to better eating and exercise habits may be the best way to ensure long-term change.

An example is the state's new Fit from the Start Initiative, which will be funded with a $150,000 grant from the Wellmark Foundation. Gov. Mike Rounds announced the grant in October during a visit by the U.S. surgeon general.

As part of the initiative, the state plans to work directly with child-care providers to increase children's access to vegetables, increase opportunities for physical activity and reduce television viewing.

Hollingsworth cautioned that although such child-oriented programs have great potential for long-term success, they might not impact overall obesity numbers in the short term.

"We are not going to see a change in our obesity rates from one year to the next," Hollingsworth said. "We aren't going to see that we've turned the tide. It's a multiyear effort."

The obesity statistics in America's Health Rankings are based on defining "obese" as a person having a body mass index (BMI) of 30.0 or higher.

BMI is equal to your weight in pounds divided by your height in inches squared and then multiplied by 703. The rankings are compiled by the United Health Foundation.

Eventually, Hollingsworth hopes that the obesity numbers will reverse in the same way that the smoking and binge drinking numbers have. She credited the educational efforts of the state and many other organizations with bringing about those changes.

South Dakota's overall rank in America's Health Rankings is 21, meaning the state is viewed as the 21st healthiest in the nation.