waiting for jkurz...
btw, it depends on your diet. Normally, you wou'd be better off with a Cheat MEAL, not DAY... it would be VERY easy to ruin a perfectly good diet week with a day of excess.
instead of cheat days, its better to have scheduled high-carbs days, where you cycle both your carbs and your cals. Those are not considered cheating, as they are part of your diet to begin with.