My back is too sore to join your push up/sit up challange, (or thats my story anyway, and I'm sticking to it), but I can encourage! How are you going to reduce? Will you weigh in weekly? Are you setting goals, or just seeing how you go? How tall are you? How have you put the weight on?
Good luck. I'm one of those dreaded lurkers, so I'll keep an eye on your progress. I find it really helpful to know that I've got company in my ups and downs diet wise, I hope you will find that too!