Is it a good idea to have one day a week, when you cheat from your normal planned diet, and eat as much as you want?
Answer:
I don't think it is a good idea. In a single day you can destroy more than a whole week's work. Furthermore, you may not really want to cheat on just this day as you might be occupied with other activities. However you can cheat occasionally. Chose a day when you have some special dish in mind and then return to your healthier diet.