Body fat / Bmi

Body Fat and BMI are two different things.

......will edit in a min... Checking something

Edit:
You can add additional things to track here -
http://www.myfitnesspal.com/measurements/check_in

After that go to the progress section in the app and tap where it says weight. This should bring up all the additional tracking stuff. Select the one you want, then click the plus sign to add a new entry to whatever you picked.