When you burn fat, you burn it all over your body. You cannot target a specific area. 7 days a week doing cardio is too much IMO, but it depends on your shape and goals. Do ab workouts and lose some weight to get some results. You wont get there if you just do one or the other.
well a buddy of mine told me when you are running ur heartrate is up and for the first 15 minutes its burning some major things that are in yoru body to function after 15 minutes it switches over to burning fat because it realizes it needs the other stuff so from what im told everything after your heartrate is up after 15 minutes its starts burning fat all over