I found one that seems to fit the bill:
https://itunes.apple.com/ca/app/my-d...477865384?mt=8
I've only been using it for a day, but it seems to work well. It keeps location services on; supposedly to tell you where you used your data. However so far it hasn't been very successful in telling me anything useful about location.
My suspicions are correct- Candy Crush is a data pig. So far today it has used 4 MB; and that's with me playing maybe 7 games.