Wii Fit Channel?
As you can see here, an image on the official Nintendo of Japan site 
reveals an interesting tidbit. Wii Fit has it’s own channel on the channel screen! The picture shows what appears to be an additional channel which is apparently to be used for additional Wii Fit functionality. The channel in question is definitely not the disk channel, which is simply in a different position, because the disk channel can be clearly seen above it, complete with the Wii Fit disk. This picture was also taken directly from the official site, so that rules out any foul play in the form of image editing. of course it is in Japanese, which makes it unclear what the channel is about.
The question is, what purpose does the extra channel serve? What possible feature could be more practical through a channel that wouldn’t work well through the disk?