In 1995, no state had an obesity rate above 20 percent. Now, all but one does.
An annual obesity report by two public health groups looked for the first time at state-by-state statistics over the last two decades. The state that has the lowest obesity rate now - Colorado, with 19.8 percent of adults considered obese - would have had the highest rate in 1995.
"When you look at it year by year, the changes are incremental," says Jeffrey Levi, executive director of the Trust for America's Health, which writes the annual report with the Robert Wood Johnson Foundation. "When you look at it by a generation you see how we got into this problem."
The study, based on 2010 data, says a dozen states top 30 percent obesity, most of them in the South. Mississippi topped the list for the seventh year in a row, with Alabama, West Virginia, Tennessee and Louisiana close behind. Just five years ago, in 2006, Mississippi was the only state above 30 percent.
No state decreased its level of obesity, which is defined as a body mass index of 30 or more. The body mass index is a measurement based on weight and height.
There was a bit of good news in the report: Sixteen states reported increases in their obesity rates, down from 28 states that reported increases last year. Levi says those increases have been gradually slowing, most likely due to greater public awareness of health issues and government attempts to give schools and shoppers better access to healthier foods.
"We're leveling off to some degree at an unacceptably high level," Levi said.
First lady Michelle Obama has tackled the issue with her "Let's Move" campaign, pushing for healthier school lunches, more access to fruits and vegetables and more physical activity. Republicans in Congress have pushed back somewhat against some of those programs, however, saying a rewrite of school lunch rules is too costly and questioning an Obama administration effort to curb junk food marketing aimed at children.
As in previous years, the study showed that racial and ethnic minorities, along with those who have less education and make less money, have the highest obesity rates. Adult obesity rates for African-Americans topped 40 percent in 15 states, while whites topped 30 percent in only four states. About a third of adults who did not graduate from high school are obese; about a fifth of those who graduated from college are considered obese.
Dr. Mary Currier, Mississippi's state health officer, says her state has struggled to drop its No. 1 status and it has been challenging because much of the state is poor and rural.
"We live in an area of the country where eating is one of the things we do, and we eat a lot of fried foods," she said. "Trying to change that culture is pretty difficult."
She says the state has had some success by making school lunches healthier, taking high-calorie foods and drinks out of school vending machines and trying to find more low-cost exercise facilities for residents of rural areas.
"It is frustrating, but we've had some progress," Currier said. "We just have to continue to work at this. It's not something that's going to change overnight."
Percentage of obese adults in all 50 states
West Virginia 32.2
South Carolina 30.9
North Carolina 29.4
South Dakota 28.7
North Dakota 28.0
New Hampshire 25.6
New Mexico 25.6
New York 24.7
Rhode Island 24.3
New Jersey 24.1
District of Columbia 21.7
More information: Calculate your body mass index: http://www.nhlbisupport.com/bmi