Sorry, LID meaning Limited Ingredients Diet. We are going to stick with the Duck and Green Pea because both cats really enjoy it, plus it's going somewhat in the train of thought that may be there are allergies/IBD at play here and this protein will work.
If it doesn't work, then we'll go with what the vet suggests - the z/d food but in canned form only (I refuse to go all dry food - it makes no sense, period).
I'm still going to be a stressed kitty mommy for the next while, watching Mr Miyagi like a hawk. I had no idea how badly constipated he was when we took him in and my fear is that he will get that way again and we won't notice - besides the vomiting and not wanting to eat (which was when he was at the worst) I truly don't remember any other signs :/
We've bought a nifty kitty water fountain to entice even more water drinking, plus I'm going to buy a few more cat toys to keep him moving and exercising to help things move along. So these things, along with the canned diet only, plus a few suggestions from the other members re: lactulose, slippery elm bark, pumpkin, olive oil - I really hope we're on our way to a healthier kitty