You don't need to count calories to succeed on Atkins, but it may help to understand that calories still matter. Atkins is not "magic" and it does not "melt" fat. In fact, after an initial flush of water weight, the weight that you will lose on Atkins will be the result of a good, old-fashioned caloric deficit. It is, however, a bit more involved than the old-fashioned "calories in minus calories burned" formula because, as it shifts your body's fuel source, a low-carb diet can speed up your body's metabolism. In addition, most people report less appetite on a low carb diet, at least initially, making it easier to acheive the caloric deficit required to lose weight.

Restricting calories to 1200 per day can prompt your body to decrease your metabolism by something like 25% to 40%, thus defeating the metabolic boost that you may get from a low-carb diet. So low-carb + low-cal is often self-defeating.

2,000 calories per day may produce the results you are looking for, depending on your activity level.