Gallup-Healthways Well-Being Index, based on 177,237 interviews conducted daily from January through June, uses self-reported height and weight to calculate body mass index scores. A number of 30 or higher is considered obese, Gallup officials say.
The overall national obesity rate of 26.3 percent this year is essentially unchanged from 26.6 percent in 2010, but higher than the 25.5 percent rate in 2008.
This year, states already high for obesity tended to get higher, and states lower in obesity are getting lower, the survey indicates.
The states with the highest rates of obesity continue to be clustered in the South and the Midwest, as in past years, while western and northeastern states continue to have the lowest levels of obesity.
The telephone survey has a margin of error of 0.2 percentage points, but the margin of error of most states is 1 percentage points to 2 percentage points, but can be as high as 4 percentage points for smaller states such as Wyoming, North Dakota, South Dakota, Nebraska and Hawaii.