nah. to burn fat you have to do cardio. run/jog/swim intensively
for >20 mins regularly, and cut down on fried/oily food, and try
to have an earlier dinner and don't eat after 7pm if possible. once
you have slimmed down, resistance training such as crunches would
be of use to tone up...yep =)
oh, i think you're doing the crunches wrongly. you're supposed to
keep your neck rather straight, not really moving, whereas your
abdominal muscles are the ones that are supposed to be
contracting...