America's Fattest Cities 2012 Slideshow

Obesity rate: 33.8 percent
Annual obesity-related costs: $182.8 million

Located in southeast Texas, this metro area includes the cities of Beaumont and Port Arthur. Oil is big business for the region, with refineries throughout the area. The metro area has been a major player in the oil industry ever since the Lucas Gusher exploded on Spindletop Hill in 1901.

According to the Gallup-Healthways Well-Being Index, the metro area could potentially save $101.6 million in medical costs if its obesity rate dropped to 15 percent, instead of the almost 34 percent it has now. Beaumont-Port Arthur is the second most obese metro area in Texas, which has a statewide obesity rate of 31 percent.

4. Rockford, Ill.

Obesity rate: 35.5 percent
Annual obesity-related costs: $179.4 million

Located in northern Illinois, Rockford calls itself the "City of Gardens" because of the 7,000 acres of parks, trails, tree-lined streets,  and public gardens within its borders. That's not the only nickname the city has had — it has also been called "Forest City," because of its woods and was once known as the "Screw Capital of the World" due to factories that produced screws and bolts. Manufacturing is still the area's biggest industry.

Rockford also ranks as the fourth fattest city in the country, however, with an obesity rate of 35.5 percent. Of the more than 152,000 people who live in Rockford, nearly 54,000 are considered obese, while 10 percent have diabetes and 23 percent live below the poverty line.

3. Huntington-Ashland, West Virginia-Kentucky-Ohio

Obesity rate: 36 percent
Annual obesity-related costs: $146.9 million

The Huntington-Ashland metropolitan area encompasses three states — West Virginia, Kentucky, and Ohio — at the point where they all meet by the Ohio River.

The metro area first gained national attention in 2008 after an Associated Press story called it the nation's unhealthiest. That led Jami Oliver to bring his ABC reality show, Jamie Oliver's Food Revolution, into Huntington, W.Va., to give schools and the town a nutrition makeover. Oliver has called his time there a success. However, the larger metro area still appears to be struggling — 36 percent of its citizens are obese, according to the Gallup-Healthways Well-Being Index, and nearly 20 percent suffer from diabetes.

2. Binghamton, N.Y.

Obesity rate: 37.6 percent
Annual obesity-related costs: $131.5 million

In the city of Binghamton, more than 17,000 residents are obese, according to rates from the Gallup-Healthways Well-Being Index. It's surprising then that 54 percent of respondents also said they exercise frequently.

Located at the junction of the Susquehanna and Chenango rivers in southern New York, Binghamton has the highest obesity rate in the state, compared to New York State's rate of just below 24 percent. Meanwhile, 27.8 percent of Binghamton's population lives below the poverty level.

1. McAllen-Edinburg-Mission, Texas

Obesity rate: 38.8 percent
Annual obesity-related costs: $410.9 million

Located near the Mexican border in southern Texas, this metro area is the most obese in the nation, according to the Gallup-Healthways Well-Being Index. If the region dropped the rate from 38.8 percent to 15 percent, it could potentially save a whopping $252 million a year in medical costs annually. That's a big savings, especially considering 50 percent of residents report being uninsured.

In 2010, 33.3 percent of the McAllen-Edinburg-Mission metropolitan area's population was obese, according to a CDC survey, so the data suggest that the country's most obese city is also getting worse, bucking the nationwide trend of stabilization in obesity rates.