49. Oklahoma City, OK

When Oklahoma City Mayor Mick Cornett noticed that his city was showing up on national obesity rankings, he made his New Year's resolution for 2008: he put the entire city on a diet, with the goal of losing a collective million pounds. (You can check out the mayor's own before/after pic at www.thiscityisgoingonadiet.com.). So the city may tip SustainLane's 2008 scales at 49th place once again, but we're excited to see what a motivated mayor can accomplish when he puts his mind to it. Residents enjoy affordable homes on large lots and zero rush-hour traffic, despite the city’s sprawl. But Mayor Cornett says gas prices have encouraged Oklahomans to trim the fat, and for many this means finding cheaper transportation options. "I would assume that this is a tremendous opportunity to advance the conversation on mass transit and density in ways that I never would have been able to do before," says Cornett. "I think that’s where Oklahoma City is right now. The citizens are becoming much more enlightened about the types of issues that you are writing about." Among other goals, the mayor wants to transform auto-centric Oklahoma City, transected by three major interstates, into a pedestrian-friendly place. And he's working to create a vibrant, densely-populated downtown. The city is also trying to bulk up its overall “greenness” with an office of sustainability—getting Oklahoma ’s environmental fitness in line with its residents’ trim new silhouettes.