[thirddan]

you should work your core all the time cuz it helps with pretty much everything...this doesn't mean do thousands of crunches...if you squat/deadlift/chinUp you will work your core, but you can throw in things like leg raises or reverse crunches also...seems like you are thinking that because you won't be able to see the six pack until you lose the fat that you shouldn't work the muscle, not true...