Fast food restaurants -- Houston has twice the national per capita average -- are partly to blame for the dishonor, Men's Fitness editor-in-chief Neal Boulton said.

"Americans ... work long hours, don't take vacations, and when you're faced with the worst nutritional choices, you indulge in those," he said.

High humidity, poor air quality and some of the nation's longest commute times also helped Texas' most populous city unseat Detroit, the 2004 heavyweight champion, the magazine said.

Houston Mayor Bill White, who has worked with a major grocer to promote healthy food and the city's public schools superintendent to improve lunch menus, called the survey "mostly voodoo and fraud."

"On the other hand, it calls attention to real issues the mayor is trying to address," his spokesman, Frank Michel, said.

The magazine said it looked at factors such as the number and types of restaurants, park space, air quality, weather and the number of health clubs.

Philadelphia, Detroit, Memphis, Tennessee, and Chicago followed Houston on the seventh edition of the fat list. Texas cities Dallas, San Antonio, Fort Worth and El Paso were in the top 14, which Boulton said was no surprise.

"It's pure big indulgence, just living big, and that's part of the culture," said Boulton.

Seattle ranked as the fittest city, followed by Honolulu, Hawaii, Colorado Springs, Colorado, San Francisco and Denver.

Austin was the only Texas city on the fit list. The state capital ranked 19th out of 25.