Welcome. Sure you can lose on this plan, but I think back to when I was a kid. I hated to try ANYTHING that was new, different.. etc. My Mom's rule was.. "Try a bite, if you don't like it.. that's fine, but at least try it". Most of the time I tried stuff and liked it. So you have to be willing I think on any plan to try new things, step outside the box so to speak because eating the same thing over and over again is going to get very boring.
Lettuce.. there are scads of varietes of lettuce. Have you tried more than a couple? Tomatoes.. is it the skins you cannot digest, or is it the acid? What about canned tomatoes.. tomato sauce.. etc.. sun dried tomatoes? I personally don't care for red meat as much as chicken or fish but I can eat it if it is sliced very thinly, like it broccoli beef or something like that. Guacamole.. there are other types of guacamole.. I actually saw Broccamole in the store the other day..
Made with broccoli. But not liking guacamole isn't the end of the world. Just like not liking cilantro or lime or any other flavors. You just experiement with a recipe and change it to your liking. They aren't set in stone and changing them is what makes it fun.
You can make very yummy meals to take to work with you that the girls will be jealous to see you eat!!