This is just my common sense, not some actual research or experience, but.. If you had an ed and your intake of calories was really low for a long time it's definitely not healthy to suddenly start eating 3000 calories? Your body will freak. It's like when you recover from a stomach flu and can only eat light food in the beginning. Your stomach isn't used to it and takes time to adjust.

I'd think building up to 3000 calories sounds pretty normal. Since that's more than an average person needs so it should give your body some extra.. stuff. For building the body back up, I guess.