Emily,
IMHO, probably the only way to decrease body weight is regular running, at least 40 minutes per day. I know it is not easy at all. You may first try walking or biking. After decreasing your weight enough to run, then you can run 2 or 3 times per week. Running not only burns your fat, but also help decrease appetite, because our liver starts to supply glucose to our blood system, making us feel satiated.
Controlling out appetite is not easy at all. I am a big eater, but run 2-3 times per week to maintain my current weight. During the winter, I did not run enough, and I run longer to decrease some fat accumulated in my belly.
At first, walking for 1-2 hours will greatly decrease your weight, but the problem is that your appetite will also increase after walking. Then you may walk longer, for example for 3 hours, to decrease your appetite.
After transition, intensive exercise will be more difficult to do.
My recent running activities:

barbie~~