First lady Michelle Obama shows off her muscles along with children at the District’s River Terrace Elementary during an event to promote physical fitness. (AP)

Maybe you can thank your neighborhood park and farmers market for this latest nod, D.C. area.

For the third straight year, the Washington metropolitan area been rated the nation’s fittest by the American College of Sports Medicine’s American Fitness Index. The index assesses the 50 largest U.S. metropolitan areas on dozens of measures, including the number of farmers markets and parks per resident, obesity rates and how often residents exercise.

Eighty percent of area residents surveyed reported exercising in the previous 30 days, although only about 25 percent were meeting the Centers for Disease Control and Prevention’s aerobic guidelines, according to the report. Twenty-five percent of residents are obese, and more than 96 percent live within a 10-minute walk to a park. Nearly 18 percent eat three or more servings of vegetables per day, the report says.

By comparison, in the Indianapolis area, which ranked last,  32 percent of residents live within walking distance of a park and about 13 percent consume three or more servings of vegetables, according to the report.

The five healthiest metro areas, according to the index:

  1. Washington
  2. Minneapolis
  3. Denver
  4. Portland, Ore.
  5. San Francisco

The D.C. area  may have received top honors in the fitness rankings, but drastic disparities in facility access and health remain across the city. Big and boutique gyms may dot neighborhoods around 14th Street NW, H Street NE and the Navy Yard, but there are no private gyms east of the Anacostia River, which has the highest concentration of the city’s poorest residents. (There are free gyms and classes at city recreation centers.)

And the index may put the area’s obesity rate at around 25 percent, but that doesn’t hold across the District. According to the D.C. Department of Health, east of the Anacostia, rates are 35 percent in Ward 7 and 44 percent in Ward 8. Ward 3, which covers most of upper Northwest Washington, has an obesity rate of just 7.5 percent.

Read the full report from the American Fitness Index here.