I wish these kinds of surveys would stop now. Nobody's ever said that the Wii was a good substitute for proper exercise. All that's been said is that's it's much better than the traditional sitting-in-one-place-on-the-sofa style of gaming.
That's it. Anyone who thinks differently is pretty dumb and we don't need regular studies and surveys to prove the point. Want to lose weight or keep fit? Try real sports or the gym. Want a fun game that's better for you than sitting around watching TV? That's where the Wii comes in.