The fact of the matter is that, even though you may be eating more protein, your body still needs energy. Protein, while the body can use it as a source of energy, is not a preferred source. However, if protein is your primary source, your body will use up extra protein for energy and use the leftovers for muscle building, store some as fat, and excrete the rest. (How much muscle one builds, of course, is dependent on many other things, like heredity, hormones, etc.)
I'd say keep some carbs in your diet. You could probably stand to cut some of them out, but, just remember, when your body demands energy, it's going to get it from somewhere, whether it be carbs, fat, or protein.