Well, Aspen, you are among the trimmest of the trim.

So keep hiking up Smuggler Mountain and slugging your wheatgrass cocktails.  But don’t let it pad your vanity too much — you are still getting fatter, like everyone else in America.

A study released last week by the Centers for Disease Control found that Colorado, at 18.7 percent, has the lowest prevalence of adult obesity. Nationally, the CDC found 25.6 percent of American adults are obese. And in Mississippi, the top-ranked state, 32 percent were found to be obese.

Statistics from the Colorado Department of Public Health and Environment indicate that among Coloradans, residents of Pitkin County are among the leanest. Data measuring obesity prevalence, sorted into 14 regions within Colorado, reveal that the section including Pitkin County has an obesity rate of only 11.1 percent. (This region also included the mountainous, ski resort-heavy Eagle, Summit, Grand, Routt and Jackson counties.)

The next slimmest region, at 16.2 percent, included Garfield, Mesa, Moffat and Rio Blanco counties.

The highest rate of obesity in the state, they found, is in the rural southeastern plains, where 35.5 percent of adults are considered obese.

Experts suggest that rates of obesity rise and fall by region commensurate with socio-economic levels. “It has a lot to do with access to higher-quality foods,” said Alyson Shupe, chief of health statistics at the Colorado Department of Public Health and Environment. “Plus, a higher income can buy a health club membership and residence in safer neighborhoods where you can avail yourself of a less sedentary lifestyle, with more biking and walking.”

In addition to higher income, mountain towns like Aspen naturally draw people with healthier lifestyles, Shupe said, which further skews the number of obese residents in such areas downward. “People will self-select to live in those kinds of communities,” she added. “They attract healthier, more active, and often younger people.”

Colorado has been the least obese state in the nation since 1990. However, back then the statewide obesity rate stood at less than 7 percent. Ten years ago, it was less than 15 percent. Which means that, as a state, Colorado is growing gradually more obese by the year at about the same rate as the rest of the nation. (The U.S. obesity rate was around 12 percent in 1990, 18 percent in 1998, rising to the current rate of more than 25 percent.)

If the trend continues here, not even Colorado will meet the federal “Healthy People 2010” objective, which seeks, through health education, to move states back to obesity rates of less than 15 percent.

“As a state, yes, we are the least obese. But the trend is still going in the wrong direction,” said Jillian Jacobellis, director of prevention services for the Colorado Department of Public Health and Environment. Even Coloradans, she said, are eating more and exercising less.

Obesity is defined as having a body mass index, or BMI, higher than 30. (Body mass index is weight in pounds divided by height in inches squared, and that number multiplied by 703.) Obesity has been linked to heart disease, diabetes and other chronic illnesses.

andrew@aspendailynews.com