Sweet ... I tossed off an answer earlier but you managed to post one of those weird things that's bouncing around in my brain. I realize now I read it too quickly:
A carb free food high in calories would be any fat, at 9 calories to the gram.
But I'm afraid you need to give me an example of a low cal food that's high in calories, because it's really bugging me, I'm starting to feel like one of those computers that's been told to play tic tac toe against myself ...
I don't think this is what you meant, is it? If it's low in calories then it's low in calories and if it's high in calories, it's high in calories. Can you elaborate?