I'm always at a loss when people think of investing in things like these.
Exercise, and don't eat junk. Get mad and say it ain't that simple, but really, it is.
Once your body gets past the cravings, your metabolism will change, and the pounds will start falling off. It's getting to this hump that is so difficult, but once you get over it, that is when you see results, and that is when you'll love sticking to a good, healthy regime.
I went from being 28% Body Fat back in July to around 13% currently. The gym I go to wanted me to be their 'Jared The Subway Guy Spokesman'
Healthy choices and exercise my friend. That's it.