Mrs LP is on the Zone diet also.
You can carry zone bars with you. If you can't find them in a store near you (and we couldn't find them on Kauai and when I was in Northern California I couldn't find them at the places that were supposed to have them), we found them online at drugstore.com. That way when the special meal turns out to really s*ck, you can just eat a zone bar instead of the meal.
As far as special meals, I think you'll have to order some sort of salad or vegetarian meal if you want to risk it. Yes, there's a list of dozens and dozens of special meals categories on the united web site.
Remember, that special meals can get in the way of upgrades.
-David