Sorry, I can't help you with the food issue. But I can comment on this.
How long have you had the cat?
Cats do not handle change well. If the cat is hiding, it's likely because he hasn't adjusted yet. In other words, he hides because he is frightened, insecure. Perhaps attempting to play with him with one of those wands with a dangling string and tassel or something on the end will help him get used to you? But basically, it will take a few weeks to a couple months for the cat to truly adjust. So just be patient.
As for the glass door, it could be one of two things:
1. If he is used to going outdoors, he's probably wanting to go back outdoors
2. Cats just enjoy looking outside. Try moving a small table or something (and stack things on top if need be) for the cat to be able to sit/lie by the window. I bought a cat ledge for my previous cat (you can get them at pet stores), and she loved it. Cats prefer heights anyway (in the wild, they will hang out in trees), so something like that might help encourage the cat to come out from the bed once in a while.