My father used to be a doctor and his one recommendation was NOT RUN. Running vigorously puts a lot of strain on you knees and lower back. You'll suffer because of this in the long run, especially in late adult hood.
You should consider swimming. Your muscles are pulling the equivalent of your body weight. But because of the medium you only feel as if you using 1/5th of your energy. The upshot of this is you see rapid fat loss and rapid muscle gain.
It is especially useful to those looking to train upper body and quads.
Also consider long term dieting takes several months before you notice dramatic weight loss. What ever you do, DO NOT crash diet or fast. This will cause temporary weight loss only which will eventually be counter productive to loosing weight permanently.