Could the Nintendo Wii Reverse the Childhood Obesity Trend?

Nintendo Wii includes, for the first time in videogame history, a really solid motion-sensitive controller. No longer can you press the "A" button to set your avatar's sword arm a-swingin' - now you have to actually swing that sword yourself. We all know how addicted videogames are to kids. Could getting them to move around for 4 hours a day instead of sitting paralyzed in front of the TV make a significant difference?