A common misconception in the low-carb world is that the end-all-be-all determiner of whether one loses or gains is how many carbs they eat. Although the low-carb diet does produce up to a 20% increase in fat loss in the long run minus water losses, it really isn't anything magical. If you eat more carbs in one day and you lose weight, if your calorie intake didn't exceed your calorie burn, it pretty safe to assume its water retention. Low-carbing has a strong diuretic effect because the lack of insulin output reduced sodium retention and causes water loss. If you have extra carbs on a given day, you may gain water weight, but not fat, depending on how much you ate. In essence, eat 500 calories less than you burn each day theoretically should result in a 1lb/week loss, 1000 calories would be 2lb/week, but metabolic adaptation can get in the way of that. I know many people on the low-carb diet that pay no attention to calories and stall frequently, which isn't because low-carbing isn't working, but because they eat too much. One could lose a pound or two in a week and not realize it because they retained some water, which is where the "whoosh" comes from. I lost 16 pounds in the first 2 weeks of low-carbing, watching my calories, but about 70% of that is water weight because you can't lose fat other than through a calorie deficit. Water weight is an exception. Atkins has alot of people convinced that the calorie rule or the energy balance rule is a myth, when really he's either lying deliberately or is very confused. A good rule of thumb when you're stalling is to eat less, exercise more, or both. You're body has to get its needed calories from somewhere, and if you're eating less than your body needs, it comes from fat, and a little bit from muscle, but much less muscle is lost while low-carbing than high-carbing.