Looking at the workouts that are on disc 1 versus everything else, you can definitely start with just that. I have the combo pack - actually the big pack which includes extreme and whatnot. Pretty much all of these are going to get your heart rate in the fat burning or cardio zone (maybe not energy for too long if your fitness level is already super high, which it might be as a runner). Maybe worth mentioning, fat burner isn't the only one that will burn fat/get you breathing for cardio.