ATLANTA - Emory University researchers say rising obesity rates account for more than a quarter of the growth in health spending.

Treating obesity-related conditions such as diabetes, hyperlipidemia and heart disease are the main reasons the health spending costs are going up.

Emory researcher Kenneth Thorpe says the impact of weight on per-capita spending is sizeable.

He adds that rising numbers of gallstone cases, some kinds of cancer and other obesity-related diseases also are causing health costs to climb.

The researchers say there is no evidence that the proportion of obese U.S. adults is declining.

About 65 percent of U.S. adults are either overweight or obese.

The study analyzed the years between 1987 and 2001 and was published this week in the journal Health Affairs.