( - Which state has the fittest residents? Make room for the new champ Montana.

The Treasure State had the lowest obesity rates in 2013, according toa new national Gallup poll. Only 19.6 percent of the population was obese, meaning that these people had a body mass index -- a ratio of height to weight -- of 30 and above.

Between 2010 and 2012, Colorado had the lowest obesity rates. In 2013, they dropped to number two.

Nevada, Minnesota and Massachusetts made up the five least obese states.

Across the nation, theCenters for Disease Control and Preventionreport that more than one-third of adults are obese. Obesity raises the risk for heart disease, stroke, Type 2 diabetes and several kinds of cancer. The U.S. spent $147 billion in 2008 dollars treating obese patients, about $1,429 more than spent on those who were normal weight.

Obesitywas declared a diseaseby the American Medical Association in June 2013, so people stopped thinking of it as a lifestyle condition.

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