My problem with overeating is boredom. I started cross-stitching more a couple weeks ago, and have found I'm no longer 'eating the afternoon away'. Mostly due to the fact that my hands have to be clean to cross stitch-so I'd have to stop, wash hands, eat, wash hands again, sit down...which for lazy ol' me that's just too much of a hassle. Knitting is also great because you can do it while watching TV (a bit harder to do with cross-stitch unless you have a big section).
I suck at knitting, but cross-stitch is super easy to pick up. Also picking up an insturment, playing video games, etc., can help a lot!