I bet if you counted the calories in/calories out it would show the calorie deficit accounting for it. The thing with low carb, in my experience, is that it does make it easier to eat less if you have the right attitude about it. I do it AND count calories. Also, just the fact that it cuts out most of the foods in the universe helps to make it an easy decision whether or not to eat something, whereas with just calorie counting all foods are available and that one bite can become 10 bites so easily. I believe those two things account for it's success rather than some trick subverting thermodynamics.