Residents of Philadelphia (incidentally, not one of America's fattest cities) lead the nation in the consumption of sweatpants.
This distinction is based on "research," but could easily, as one writer Randy LoBasso suggests, been achieved by looking directly at the residents of the city's Fishtown neighborhood. Though the area's restaurant and bar scene has rapidly gentrified, the area's slovenly aesthetic hasn't matched the upswing in fancied pizza.
Full disclosure, I lived in Fishtown. While there, I wore sweatpants. As did my disability-check cashing neighbors (who loved OC) and my former college roommate/best friend. Sweatpants in Philadelphia are not fashion-forward. Instead, sweatpants in Philadelphia are a uniform of utility. Nobody wants to mix with blue bloods like Mortimer and Randolph. Everyone wants to drink Lagers at Les & Dorien's, while pregnant teenage girls smoke cigs and sing karaoke. It's a town of pure, unadulterated American pleasures.
If one needs style icons, here is an esteemed, if incomplete, list of men who have influenced Philadelphia's favored sweatpant sizing: Allen Iverson (pictured above), Beanie Sigel, Nico the Beat, Jakk Frost and former Eagle's head coach Andy Reid.