Getting them healthier is my main concern because a healthy person will lose fat, get bigger muscles, get more toned and fit a lot easier than someone that is unhealthy. So in order to get them healthier, I don't advocate a low calorie diet or counting calories, I advocate a highly nutritious diet.
I'm not concerned with how many calories my clients eat, what is most important to me is that they are eating enough nutritious food. By nutritious I mean vegetables, lean sources of protein, fruits (especially berries) and nuts. My philosophy is that by eating nutritiously, you become healthier. By eating nutritiously and becoming healthier you feel better, workout better and recover from workouts better. The side effect of all that is that your body will look better.
My point to all this is that you should concentrate on becoming healthier and the rest will follow.