While crunches alone won't trim your middle, you don't want to skip them altogether. Once you're incorporating cardio regularly and the fat starts to melt away, you want to reveal toned abs underneath. Complement your cardio with strength-training sessions that include core work such as these plank variations, these core-carving yoga poses, or this 10-minute ab workout using hand towels. Simply balancing on one leg on a BOSU will target your core too.