In talking to lots of low carbers, I've found that everyone is different when it comes to the calorie issue. Some need to monitor their calories and stick within a certain range in order to lose and some don't. Personally, I haven't been paying much attention to calories until very recently.

I'm still not obsessing about them, but I am trying to stay under 2000 calories on most days. I think an occasional higher calorie day may actually be good for the mix. Our bodies are pretty efficient and when they get used to a certain number of calories on a regular basis, they become adept at functioning at that level and the initial weight loss can stall. By varying my calories, my body doesn't really have a chance to adjust. I use Fitday.com and check my averages on a weekly basis. As long as that comes in under or around 2000, I'm good with that, even though it may mean one day was 2600 and another was 1600 during the week.

My advice would be to do your own experimenting and see what your body seems to do best at.