MREs at a Glance
So, on the whole, MREs vary pretty widely. Some of them are actually decent to eat, especially if you heat them up. Other ones are pretty ambitious to even call themselves food -- like, I wouldn't feed them to my dog, and he eats all sorts of terrible things.
Once you eat MREs for even a couple days straight, they all start tasting the same. And they carry with them the universal truth of constipation -- serious, unrelenting constipation. That's probably the worst part of MREs for days at a stretch. No, you won't starve to death, but you're going to be spending some time at full grunt trying to get them out of you.