I don't think that's a short way of saying the same thing though, for the kind of consequences you mean at least. Imagine if I were a vegan for ethical reasons. It'd be fine for me to say "I don't eat meat", but a lie to say "I can't eat meat", since I'd be perfectly capable of doing so, and be fine if I did, and just not want to anyway. Contrast this with if I had alpha-gal syndrome and someone me offered me a steak. In that case, I could truthfully say "I can't eat that".