Well, as Satirist so rightly pointed out, diet and cardio workouts have to work together, trying just one or the other will not help matters much. I know people who end up eating more because of going to the gym, when in fact they need to be eating less, or at least reducing their carb intake...I find that eating only raw food (fruit and veg basically) till the evening meal works well for me, but these things are very personal.