You just do it. Do you want a healthy body? Do you want it badly enough to stop the insanity? So you stepped down off the wagon, now pick yourself up, dust yourself off. Write a journal on how it made you feel and start eating healthy the very next meal. Don't wait another day, or another week. Do it now. Everyone makes stupid choices from time to time. You get to do over...that is the difference between success and failure.... Quiting = Failure. If you refuse to quit then you can't call yourself a failure. Keep moving forward.