I am just starting to count calories. I do think they count. I haven't yet determined the magic number of how many are "too few" and cause metabolism to slow down. I think it's less than BMR, but don't really have any proof of that.

I think the real key is to increase caliries burned rather than decrease calories eaten to achieve optimal weight loss. So maybe a good goal would be to eat the same number of calories as BMR (or even slightly less), then exercise enough to get the "right" number of calories burned to achieve your weekly weight loss goal. Right now, I'm targeting to burn 741 calories more per day than I eat, which equates to 1.48 pounds per week weight loss.

Good luck!