I explained this very clearly. The exercise of course has to consume calories. But that doesn't mean they have to be calories in excess of your base metabolic rate. What happens is that your base metabolic rate decreases more or less commensurately with the amount of extra calories you're consuming through excercise. If your BMR was 2000 Cal/day when doing 0 calories from excercise per day, and then you start exercising for 300 Cal/day, your BMR will decrease to about 1700 Cal after some time of maintaining this routine.