Family Guy did it: https://www.youtube.com/watch?v=d0aIqx1McVI There's a song called "The Air Is Getting Slippery" by Primus, which is where this tune seems to have come from, but there's nothing explicitly anti-fat about its lyrics so that was a dead end. The music just seems to parody the 'fat waddle' perfectly, like you might expect to hear in a Looney Tunes kind of cartoon.