Wichita ? Kansans are getting fatter, with more than a fourth of them now saying they are obese, according to a report released Tuesday by the federal Centers for Disease Control and Prevention.

That’s an increase from the 2005 version of the report and follows a national trend: Nine states now have obesity rates of 30 percent or greater, compared to no states in 2000 and three in 2005.

The rates are underestimated, the CDC said, because they are based on what 400,000 people nationwide told researchers who asked for heights and weights during a phone call.

Both men and women tend to say they are taller than they are, and women often say they weigh less than they do, the CDC said.

The new report shows that between 25 and 29 percent of Kansans say they are obese, meaning they have a body mass index of 30 or more. Body mass index, or BMI, is a calculation of height and weight. A 5-foot-4 woman who weighs 174 pounds or more, or a 5-foot-10 man who weighs 209 or more would be considered obese, for example.

Preliminary data based on 2008 information showed that 28.1 percent of Kansans are obese.

The obesity rate is important because people who are obese have medical costs that average $1,429 more than those of normal weight, the CDC said. In 2008 dollars, medical costs associated with obesity were estimated at $147 billion.

Obesity also is a factor in heart disease, stroke, diabetes and some cancers.

“Obesity continues to be a major public health problem,” CDC director Thomas Frieden said. “We need intensive, comprehensive and ongoing efforts to address obesity. If we don’t more people will get sick and die from obesity-related conditions such as heart disease, stroke, type 2 diabetes and certain types of cancer, some of the leading causes of death.”

Jason Eberhart-Phillips, the state’s health officer, said, “While this study shows that 28.1 percent of Kansans self-reported being obese, this isn’t just a problem for 28.1 percent of Kansans. This is everyone’s problem.

“Obesity is a complex problem and requires not only personal action, but community action as well,” he said. “People in all communities should be able to make healthy choices. To reverse this epidemic, we need to change our communities into places that strongly support healthy eating and active living.”

The report, “State-Specific Obesity Prevalence Among Adults — United States, 2009,” says the self-reported number of obese American adults increased by 2.4 million between 2007 and 2009. It’s based on new data from the Behavioral Risk Factor Surveillance System, which has been regularly updated since 1984.

Nationally, 26.7 percent of American adults are obese, the report says. Only Colorado and the District of Columbia had obesity rates of less than 20 percent. The rates ranged from 18.6 percent in Colorado to 34.4 percent in Mississippi.

The nine states with obesity rates of 30 percent or more are Alabama, Arkansas, Kentucky, Louisiana, Mississippi, Missouri, Oklahoma, Tennessee and West Virginia.

The obesity rate was highest — 31.1 percent — among those ages 50 to 59. It was lowest in those between 18 and 29 and those 70 or older. The highest prevalence was among non-Hispanic blacks overall, whose rate was 36.8 percent, and non-Hispanic black women, whose rate was 41.9 percent. The rate for Hispanics was 30.7 percent.