Helio Castroneves -- NO CHUBBY DRIVERS IN INDY ... 'Only NASCAR'

IndyCar drivers = lean, mean driving machines.

NASCAR drivers = fatties.

... this according to IndyCar stud Helio Castroneves.

You gotta watch this clip -- Helio is hilarious ... and picks a "Talladega Nights" style feud with NASCAR ...starting with their "beer bellies."

Jean Girard would be proud.