In a forum I am a member of, they were talking about the possibility of losing weight after a fifteen minute workout. It's actually quite possible, especially if you're into Tae Bo exercises. Of course, this is just a starter program. The more you get fit, the more you'll have to increase your fat-burning and muscle-toning regimen.
But don't go too harsh on yourself. It took me a week to catch up with what Billy Banks was asking in this video. If you're overweight or obese, don't abuse your limit just yet. It's always better to start with walking or jogging just to shed those extra weight (and increase your stamina) before delving into this kind of exercise.
Once your at it, remember that if at first you might feel your knees buckle after 2 days of doing this straight, give it a rest or tone it down a little.
And lastly, to gain the maximum benefit of Tae Bo, check your form and posture in the mirror once in a while. Without an instructor, you might just be surprised how often solo doers do incorrectly.