Slang term for a guy/girl who likes fat chicks/dudes.
Modified from the term Mile High Club
, which is a ficticious club that requires a member to have sex during a flight that will be traveling a mile or more above the ground, the Mile Wide Club is a ficticious group whos members have had sex with so many large people, that when you add the widths of their asses together, it equals a mile or more.
Eric: Man, if Ben bangs that cow, Lois, I bet he can get into the Mile Wide club ... her ass has to be at least 30 inches across !
Jeff: You aren't kidding, dude ... he goes for the big'uns !