Men's Health says that Houston is the fattest city. You would think that the criterion might be weight. Instead, the criteria include "fast food restaurants per capita, TV watching, air quality, and parks." Air quality? I guess distilling oil makes you fat. I can kind of see fast food as a proxy, but what type of restaurant qualifies as "fast food" -- Subway, Boston Market? This is just flawed, but will be seen as fact by most. Sad.
Even empirically, I've been to both Houston and Seattle. There is no noticable difference in fatness. However, a place like Chicago (#5) is definitely fatter. I've heard that Madison (not ranked) is even worse.