I can't speak to Callanetics specifically either, but I do really well on a barre rotation because barre burns very little calories, and therefore keeps my appetite low. Which in turn makes my calorie intake less which makes me lose weight. But barre still tones the muscles great despite the low calorie burn, so you can get that inch loss + weight loss from a lower calorie diet.
I love doing HIIT style, running, plyo, heavy weights, kettlebells, etc. workouts but they make me ravenous.
I ended up mostly giving these up because I just didn't want to battle my appetite anymore.