I started this workout program having spent years lifting, with additional cardio on the treadmill. This program, by far, pushed me to a new limit. With an upper-body focus with cardio - my metabolism was going for the rest of the day and I could feel my body transforming. I have been using the system for months now, have slimmed down and see increased muscle tone.
I would recommend that you either have weights to complement the program or make certain you have household items in the house that you can use as an alternative. Very good program; however, if you are new to working out, modify and then increase your efforts.