You have to stay on plan. Exercise is also key to keeping weight off when you get to goal. You have to change the way you eat for good. That doesn't mean you can't have special meals, but it's good to plan for them. Get really serious and stick with it. There will always be some birthday, wedding, holiday, etc. If you fall off with one meal, get back with on the next meal. Don't wait till the next day. If you know you will be indulging, get plenty of exercise and eat a lighter high protein breakfast and lunch. We are getting in toward a difficult time of year. Make good choices and good luck!