I usually try to figure out what I'm craving and find a low carb substitute. For example, the smell of the mint Girl Scout cookies they kept putting by the coffee pot at work was driving me nuts! I decided it was the mint I really missed, so I bought some peppermint herbal tea and added a packet of Splenda to the cup. It satisfied my mint/sweet cravings. If it's crunch (as in chips and dip) that I miss, I make some pepperoni crisps and avacado dip. Also, a couple of olives go a long ways toward satisfying some cravings.

It just really isn't worth cheating -- you'll only feel guilty and bad about yourself afterward, so you won't even enjoy what you had!