The 21-Day MetaShred is a fitness system that’s scientifically designed to make every single minute of your workout more effective. The secret: a cutting-edge method called “high-intensity metabolic cycling.” In each 30-minute workout, BJ Gaddour, CSCS, not only varies the exercise selection, order, and tempo but also manipulates the amount of time you work and rest. This makes your body highly inefficient at performing each routine, which maximizes your calorie burn and supercharges your metabolism.