Houston's blame for being U.S.'s fattest city: Big Macs

Houston, Texas is the United States' fattest city the past three years according to Men's Fitness magazine. Now, their sponsoring their lean campaign: Get Lean Houston.
Their sponsor: McDonalds.
Sure, McDonalds has some foods that are low in fat, but still they serve burgers.
How can a big fast food chain sponsor a city to get even leaner when they serve burgers?!
Earth to Houston: Get a Reality Check!