fat as a pig
(as) fat as a pig
Exceptionally fat or obese. I love going to the beach, but I'm going to look as fat as a pig in this swimsuit.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
*fat as a pig
exceptionally fat; grotesquely fat. (*Also: as ~.) If I don't stop eating this cake, I'll be fat as a pig! You really ought to go on a diet; you're as fat as a pig.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.