I'm going to cause my roommate to switch dorms
Why don't you want your roommate anymore?
He spends too much money on food.
Not everyone is going to get along and that's okay, you have the option and right to switch around until you find someone compatible. However, it's also important to be able to compromise and deal with roommates who aren't perfect. As long as they are still able to pay their rent, I think their food budget shouldn't be an issue.
I think the campus food isn't very good anyway.
If his food spending is actually having an impact on you, then that's a good reason to want to switch or look for a new roommate. However, it's unlikely you're going to find a roommate who is not going to have some habits that annoy you. Roommates need to learn to deal with the minor annoyances that come with living with someone else.