I'm learning how my body works in terms of fat and muscle levels. My main tool is a body composition monitor from Omron. I just bought a version that is made for the Japanese market, with no manual available in English. I'm making one, and I'll be glad if you help me. You can fill issues on Github or send me pull requests.
The manual: https://github.com/petersenna/HBF-701/raw/master/pdf/hbf701.pdf
Github page: https://github.com/petersenna/HBF-701
HBF-701 at Amazon: http://www.amazon.com/KARADA-Scan-Composition-HBF-701-Japanese/dp/B001EUNKHK