I have not been on Atkins long enough to be able to give you guys any advice on cheat days...however, I have been on a general diet for a while, and, I have found that cheat days helped me to lose more weight than I could before. Actually, most of my cheat days weren't planned and would usually be a couple of days. When I would get on the scale, I would find that I lost a couple of pounds.
And, the few times I got off my diet for a week at the time? Well, I didn't lose (and didn't gain), but, when I did start dieting again....I would drop like 4 pounds in a day or two. It's like my body was saying, "Ok, we can let go of this fat...she's not starving."
I think it has to do with keeping your body guessing and not knowing what you are doing. Your body can't get used to a set pattern, so it can't get so efficient that weight loss stops.
However, if you are the type of person that can't stop with just one...I wouldn't do it. It would be better to lose weight very slowly, than to take a chance going back to old eating habits.
JMHO, and I just started induction yesterday....I plan on having a cheat this Sunday (my birthday) and will let you know how it goes.