Joseph R. Gannascoli, the guy who plays everyone’s favorite gay mafioso on The Sopranos, has leveraged his recent weight loss into a new gig. Beginning next month, he’ll host “Chewin’ the Fat,” a radio show about healthy eating, on FM 98.5, WBZB. Using his show-business clout, Joey G. has lined up C-list guests ranging from former Baywatch hottie Gena Lee Nolin to Jimmie “Dy-No-Mite!” Walker of TV’s Good Times. (The radio show has an odd seventies vibe; 1976 Olympic superstar Bruce Jenner is even mentioned in promotions. There is no possible way Gannascoli will not be wearing a velour tracksuit during the interviews.) Each week the show will promote a new diet product for Joey G. and his guests to try. Of course, it goes without saying that we’re waiting for the episode where Joey G. taste-tests johnnycakes. That’s one treat you can’t eat just once.