I did...twice. The first was an all out pig out. I didn't feel awful at all, but it set me back a full week on the program.
The second time was a smaller set back, but still, is wasting my time and making it so I need to stay on the program in phase one that much longer.
If you do the diet in the correct format and each phase properly, the REWARD in food terms is that you can have planned cheat days as your regular week.
Overall, I keep telling myself it is a short time frame in perspective to your life.
When I feeeeeel I need to "cheat" now, I am using an extra restricted food, or jazzing up a regular packet to feel more full or satisfied. It seems to not affect my weight loss as long as it isn't every night, and I do exercise almost every day too, which I think helps.
Good luck...stay the course. I'm working it and it does take effort!