Im not sure I buy into the whole "3500 calories is a pound" idea. Because on atkins, its not about calorie reduction. How would you explain people losing 15 lbs in a month? Granted part of it is water, but with the whole 3500 calories= lbs theory, people would lose maybe 4 lbs a month. So knowing this, isnt it safe to say that gaining weight works the same way? Im sure most of it was water, but im sure some of it was also fat. I almost didnt start atkins for this very reason. I believe that you gain weight alot faster by stopping atkins, then by stopping one of the low fat diets. This is my own personal opinion, I really dont have any facts to back up my statement. Maybe it has something to do with ketosis.