We asked Jillian what type of exercise is the most effective for reducing overall body fat, and she said the exercises that burn more calories, and therefore burn more stored fat, are HIIT, resistance training, functional fitness (exercises that incorporate multiple muscle groups), and circuit training.
Jillian went on to explain that while you're working hard to burn overall body fat, you'll want to condition the muscles underneath the fat so when you lose that top layer, your tummy will be toned. She recommended doing "functional exercises like push-ups, mountain climbers, planks, lunges with chop (torso rotation), etc." These moves all "burn calories and condition your core."