Hey! If you get the right tapes, like the ones that include toning, stretching, warm-ups, and aerobics, they will work. You can't exactly know how much you will lose with them though because everyones body is different. Just remeber that 80% of losing weight comes from eating healthy, so its not just based on exersising. You need to make a concious effort to eat right, and you will succeed. Good luck! ~*ERIN*~