A survey of more than 350,000 Americans for the new Gallup-Healthways Well-Being Index has revealed the nation’s fattest and skinniest cities — and three Colorado cities have landed in the top 10 skinniest positions.

Overall, the nation’s average obesity rate last year was around 26 percent, and adult obesity rates were higher than the goal-rate of 15 percent in all but three of the 190 metropolitan areas surveyed, including Boulder and Fort Collins.

So who won the dubious title of fattest? The metro area of McAllen-Edinburg-Mission, Texas, which has an obesity rate of almost 39 percent.

On the other side of the scale, the svelte residents of Boulder and Fort Collins were only about 12 percent likely to have too much excess poundage. And with Colorado Springs also landing in the “skinniest” top 10 list, Colorado takes the crown of the Skinniest State.

Carrying too much weight isn’t just a matter of vanity — it affects healthcare costs, too. Gallup estimates the high obesity rate in the McAllen-Edinburg-Mission metro area means it pays $400 million annually in unnecessary health-care costs. Reducing that rate to 15 percent would save the area as much as $250 million every year.

Here are the top five fattest metro areas (and the percentage of residents deemed obese):

  1. McAllen-Edinburg-Mission, Texas: 38.8 percent
  2. Binghamton, N.Y.: 37.6
  3. Huntington-Ashland, W. Va., Ky., Ohio: 36.0
  4. Rockford, Ill.: 35.5
  5. Beaumont-Port Arthur, Texas: 33.8

Here is the Skinny Top Ten:

  1. Boulder, Colo.: 12.1 percent
  2. Bridgeport-Stamford-Norwalk, Conn.: 14.5
  3. Fort Collins-Loveland, Colo.: 14.6
  4. Barnstable Town, Mass.: 15.9
  5. Santa Barbara-Santa Maria-Goleta, Calif.: 16.4
  6. Naples-Marco Island, Fla.: 16.5
  7. Trenton-Ewing, N.J.: 16.8
  8. Provo-Orem, Utah: 17.1
  9. Colorado Springs, Colo.: 17.4
  10. San Francisco-Oakland-Fremont, Calif.: 17.5