Have you ever seen a person got slim body only because remains standing for half an hour daily. Yes this can be possible with a special posture. This exercise is also a part of yoga and stretching exercise. In this exercise you have to only stand straight with both of your hands up and to stretch your body upwards as you are trying to touch anything up to you which you are not able to touch.
If you are quite healthy and want this exercise to gain power than you should give more stretch to your body and you are fattier and not interested to give your body more pain than you only just stand in the above posture than see the action of the exercise. When you feel that exercise is not applying the appropriate pressure on your body than work a little more hard with it. Stand on your feet-forefingers and by joining both hands stretch the body.
The other benefit of this exercise is that it will make your body in straight line. It makes your hips and stomach slight inside like to look smarter. In young age in which you can increase your height it also works on that too.