This online tool is designed to allow you to export weight, bmi, and other fitness data from the Wii Fit for analysis on your computer or upload to other systems. It accepts a back-up data.bin file from Wii Fit and Wii Fit Plus games.
The resulting data is available in xml, csv, and direct import into excel. WiThings support allows direct import into the WiThings website.
On your Wii, back up your Wii Fit data to a SD card.
Wii Options > Data Management > Save Data > Wii > Wii Fit ( or Plus) > Copy > Copy to the SD Card? (Yes)
Insert the SD Card into the computer
Open the browser dialog below, navigate to this path on your SD card and upload the data.bin file.
private/wii/title/(RFPE or RFNE)/data.bin
Upload the data.bin file here
See some sample data