I don't know about the plan you're on, but for me it's the planning that keeps me on track. No matter how late I go to bed (ie. if I forget) I take a few minutes and plan everything I'm going to eat for the next day. Part of this is because I keep a lot of meals/parts of meals in the freezer, so I know I have to take something out to thaw. However, knowing what I'm supposed to have for lunch, snacks, etc. keeps me from just grabbing things.
Also, I'm a calorie counter, so if and when I really feel I have to have something I just work it in. ie. over the last 3 weeks I worked 4 ice cream bars into my daily calories (and they were really good, 200 cals each - not diet bars). I don't feel deprived very often because if I really want it, I just figure out a way to have it.
Best of luck.
