It would come off the 1500. Don't forget that you can still eat the whole 1500 (or more) if you want to, but you would then just need to burn off the 7000 (+ any extra you ate) by doing exercise.

(e.g. I've been eating 1200ish per day and burning off 500 on our exercise bike every 2-3 days - so on these days it is like my calorie intake is only 700)