I'm sure I spotted someone on here who said they eat with them in
Ah, yes, that would be me!
My orthodontist -- who is an Invisalign Premier Provider and one of the top 100 providers in the U.S. -- recommends eating with them in. The reason is simply that they work better. I am on tray 12 of 33 and I my ortho is very pleased with how things are going. I am on a 10 day cycle. I remove my aligner promptly and clean it and my teeth every time I eat or drink anything.
DISCLAIMER -- Please note, I do not wish to be shot down in flames for eating with my aligner in. I am not telling anyone else to do it, I am just responding to stickytiff's question. It is a personal decision and it's working for me! End of disclaimer!
OK, so the only thing my ortho says not to do is drink very hot liquids -- everything else is fine. I do not eat meat, so I don't know how that would work, but I eat almost everything else. I have only one aligner and fixed braces on the bottom, so I avoid crunchy foods that could dislodge my fixed brackets, like hard candy or raw carrots etc. If you eat potato chips or other foods like that, the aligner will get a little scuffed where you chew -- it won't feel so smooth and that could be annoying to some people. Also, I once made the mistake of eating a chopped parsley dish with my aligner in and that was not a pretty sight! Usually, though, nothing gets stuck in my aligner and I've certainly never warped or broken an aligner. As I said, I whip it out immediately after eating, so there's no danger of anything sitting in the aligner, eroding my tooth enamel. The aligner does not stain, even if I eat curry and drink red wine. I have 11 perfectly clear used aligners to prove that!
I think that having only one aligner makes it a lot easier for me to eat, as I have a regular tooth surface on the bottom. Maybe eating with two aligners would be a different ball game.
I hope this helps, stickytiff.