I reckon it does. Wii fit has a range of muscle workouts and aerobic excersises to burn fat. It stretches many muscles, and is very accurate. However, if you are still a child, it may not mark you...
If you mean height wise, there is not a man made substance that can literally make you shrink. However, often times as we age, we lose muscle, and bone. This can literally cause inches of shrinkage....