Coffee can make the body act like your a diabetic. I think some fruit juices are acceptable, apple juice comes to mind but I better let someone else comment on that. OJ however I would guess not (but again, listen to someone else).
There is some Crystal Light type drink that uses Stevia or something isn't there? I forget the name/brand.
You could also try vegetable juices I suppose. Just stay away from carrots, tomatoes, and other sugary/starchy vegetables and watch portions. Celery juice is quite good, IMO. Mercola has some good articles on vegetable juicing I recall. (I refuse to link them, however.... LOL!)