This may come as a really stupid question, but, if i do aerobics, or whatever, so many times a week, will my abs be flat and toned or will they stay flabby until I do sit-ups???
Flab is a function of fat. Lose the fat and you lose the tummy. However, by building muscle by doing situps (and other, better ab workouts) you will put muscle underneath. Conceivably it's possible to have tighter abs without needing to get down to a tiny bodyweight - but that region is always going to have a soft layer above it until you get rid of the fat.
