I'd recommend just doing a cheat meal..some people do a cheat day, but I think such a day can seriously be counter productive if you go 'balls out.' You can easily take in a massive amount of calories on a binge if you let yourself go..
As far as workouts are concerned, I'd honestly stick to the 5x5 while trying to keep improving your lifts..and at the very least maintaining them. Don't overdo cardio and lifting while depriving yourself of calories or you will find yourself at a catabolic plateau very quickly..