How fit is your city? That's a good question. Now, you may just be able to find out how it compares to other cities across the United States. A new Gallup study reveals which cities are the fattest and thinnest across the country.

The researchers used telephone interviews conducted as part of the Gallup-Healthways Well-Being Index survey in 2012 and 2013, with a random sample of 531,630 adults between the ages of 18 and older.

So what did the new Gallup study find? It turns out that Boulder, Colo. Is the slimmest city in the U.S. In fact, it as an obesity rate at a mere 12.4 percent. That makes Boulder the slimmest city almost every near since Gallup and Heathways began measuring in 2008, with the exception of 2009, according to Gallup.

While Boulder was the thinnest city, though, Huntington-Ashland metropolitan area, which straddled West Virginia, was the most obese city. It has a staggering obesity rate of 39.5 percent. It was followed by the McAllen-Edinburg-Mission area in Texas, which has an obesity rate of 38.3 percent.

But how did major cities fare? It turns out that the largest major city was Memphis, TN with an obesity rate of 31.9 percent. The thinnest was Denver-Aurora, CO and San Diego in CA at 19.3 percent.

While some cities are doing well, though, the U.S. overall isn't doing the best as far as its health goes.  In fact, the U.S.'s obesity rates jumped to 27.1 percent last year, which is the highest that the Gallup has recorded since beginning its tracking, according to Time.

"Rising obesity rates have significant health consequences for both individuals and communities of all sizes," said Janna Lacatell, Healthways Lifestyle Solutions Director, in an interview with Gallup. "In order to combat the trend and encourage individuals to make healthier choices, community-based policy and environmental approaches can, and should, be used."