Alright, I got my husband to explain it to me. I figure he should know, he cut a ton of weight and got extremely fit a few years back (he's a Marine).

Here's the explanation I got: "You should try to maintain a net base of 1200 calories, so if you plan to burn 300 through exercise, eat 1500. You aren't doing yourself any favors if you're netting well below 1200, because even though you'll probably drop weight, you're gonna feel like [crap] because your body is really draining on itself, instead of the food you're eating. It won't actually slow your metabolism, working out does in fact keep it moving, but you'll be more likely to cheat, binge, or just totally fall off the wagon because you'll feel pretty terrible. Bottom line, eat healthy foods when you're hungry, keep working your *kitten* off and the weight loss will come. Don't worry so much about counting calories."