I had such a fit and medium muscular toned body and i am happy with it. Except my stomach!

Some expert said, sit-up exercise is NOT SUITABLE to loose stomach fat. It it just for SIX-PACKS making. Otherwise (for who has fat stomach), the muscle that you gained from the sit-up, will push your stomach ahead and it will looks larger to the front (fat + muscle). How true is this fact?

Other than sit-up or any kind or exercise (assuming the fact above is true), what is the best way to loose fat of stomach fast? (at least in 1-2 months time)

Expert, please advise.

I’m a skinny kid. I’m in shape and i swim 2 hours and 15 min on an advanced swim team 4 times a week. This summer im life guarding and would like to have a six pack or at least a more well toned body. What exercises should i be doing. I’m 15 years old 6 foot 3 and weigh 150 pounds. I’m planning on lifting weights this summer but in till then what should i be doing to get a six pack; or more in toned abs?