Loosen the belt buckle another notch America: Obesity rates continued their climb in 31 states last year. No state showed a decline.

Mississippi became the first state to crack the 30 percent barrier for adult residents considered to be obese. West Virginia and Alabama are just slightly behind, according to the Trust for America's Health, a research group that focuses on disease prevention.

Colorado continued its reign as the leanest state in the nation with an obesity rate projected at 17.6 percent.

Texas tied with Missouri for the 12th-highest rate of adult obesity at 26.3. Texas also had the sixth-highest rate of overweight children ages 10 to 17. Texans also ranked poorly in physical activity, with 27.4 percent of adults not engaging in any physical activity. On the more positive side, Texas is one of 17 states requiring school meals to meet higher standards than required by the U.S. Department of Agriculture.

This year's report, for the first time, looked at rates of overweight children ages 10 to 17. The District of Columbia had the highest percentage — 22.8 percent. Utah had the lowest percentage of overweight youth — 8.5 percent.

Officials at the Trust for America's Health advocate for the government to play a larger role in preventing obesity. People who are overweight are at an increased risk for diabetes, heart problems and other chronic diseases that contribute to greater health care costs.

"It's one of those issues where everyone believes this is an epidemic, but it's not getting the level of political and policymaker attention that it ought to," said Jeffrey Levi, the organization's executive director. "As every candidate for president talks about health care reform and controlling health care cost costs, if we don't hone in on this issue, none of their proposals are going to be affordable."

At the same time, many believe weight is a personal choice and responsibility. Levi doesn't dispute that notion, but he said society can help people make good choices.

"If we want kids to eat healthier food, we have to invest the money for school nutrition programs so that school lunches are healthier," he said. "If we want people to be more physically active, then there have to be safe places to be active. That's not just a class issues. We've designed suburban communities where there are no sidewalks for anybody to go out and take a walk."

To measure obesity rates, Trust for America's Health compares data from 2003-2005 with 2004-2006. It combines data from three years to improve the accuracy of projections. The data come from a survey of height and weight taken over the telephone by state health departments.

Generally, anyone with a body mass index greater than 30 is considered obese. The index is a ratio that takes into account height and weight. The overweight range is 25 to 29.9. Normal is 18.5 to 24.9. People with a large amount of lean muscle mass, such as athletes, can show a large body mass index without having an unhealthy level of fat.

A lack of exercise is a huge factor in obesity rates. The Centers for Disease Control and Prevention found last year that more than 22 percent of Americans did not engage in any physical activity in the past month. The percentage is greater than 30 percent in four states: Mississippi, Louisiana, Kentucky and Tennessee.

Meanwhile, Minnesotans led the way when it came to exercise. An estimated 15.4 percent of the state's residents did not engage an any physical exercise — the best rate in the nation. Still, the state ranked 28th overall when it came to the percentage of obese adults.

Another factor in obesity rates is poverty. The five poorest states were all in the top 10 when it came to obesity rates. An exception to that rule was the District of Columbia and New Mexico. Both had high poverty rates, but also one of the better obesity rates among adults.

Obese America Fast Facts

— still climbing in 31 states

— no states decline

— Mississippi first to crack 30 percent barrier for obese adults

— Colorado is leanest state (17.6 percent obese)

— District of Columbia has highest percentage of obese children ages 10 to 17 — 22.8 percent.

— Utah has lowest percentage of obese youth — 8.5 percent.

Calculation

— anyone with body mass index greater than 30 is considered obese

— overweight range is 25 to 29.9.

— normal is 18.5 to 24.9. (index is ratio that takes into account height and weight)

Factors

lack of exercise

— Centers for Disease Control and Prevention found last year that more than 22 percent of Americans did not engage in any physical activity in the past month.

— percentage is greater than 30 percent in four states: Mississippi, Louisiana, Kentucky and Tennessee

poverty

— five poorest states all in the top 10 for obesity rates

On the Web:

Trust for America's Health: http://healthyamericans.org