The next slice of pizza you eat will make you explode. lol
You have to be honest and ask yourself how bad do you want it. Losing weight is a beast. It takes a heavy duty commitment. Personally I'd forget the whole idea of a diet per say, think of this as a life change. What helps me through tough food times is being involved in the journey ala posting on forums, reading fitness books, watching kickboxing and bodybuilding dvd's etc...
Also if I do mess up, which I do, I get honest about with someone and move on. Good luck.