Lemme tell you something. Your body acts oddly, differently than you would expect. Whenever you work, you gain muscles in the areas that you are working, right? Well, your fat doesn't work the same way. Most girls gain/lose in their breasts (disappointing, I know!). So even if you go biking, you could lose belly fat instead of leg fat, and if you do situps and have rockhard abs, you could still have that belly fat. It's really dependent on what your body is and how it acts.
I agree with the above. Try sweating. Try the simple rule. Make more go out and than you want to go in. If you WANT to do the pooping method, eat lots and lots and lots of fiber. Make things easy on your digestive system. Drink lots of fluids so that you retain very little and get rid of a lot, and take any opportunity to get rid of fat by sweating.