I don't know how to do any type of fat test, but I know there are some body fat percentage equations out there, just search some on the net. Anyway, you've probably heard about all the tips like exercising and cutting meals in half, and I suggest you try those. And if your one of those people that aren't very motivated and break your diet promises, you can always make up the difference in exercise, and nobody even has to know. You can run in place in your room or do jumping jacks, you can take nice long walks, or even try out for a sport. There are many ways to lose weight, and many ways that work.