It’s possible to take Wii Fit data and extract it into a usable format! I was looking for this, so my data won’t be locked into a proprietary system (in case I decide to start tracking my weight in a different way) or in case I’d like to compute statistics with the data (which I will, eventually.) I’m sure I could handle the current level of commandline-foo required, but the author is planning on making it much easier:

My eventual goal will be to create an online parser where people can upload data.bin files from their wii fit save and have that data file converted into a csv that can be downloaded. Right now, this is a simple log of my sources – if you have ideas or other knowledge, please share it!

I haven’t run the code yet, but it doesn’t look like it extracts steps or waist size, which would be nice independent variables.