What Kind of Diet Should I Follow to Get a Six-Pack?

You're going to want to vary your exercise plan some. As a girl, my body works a bit differently, but my physical appearance has typically been tied much more to my physical activity than to my diet (unless I'm eating remarkably badly). I've lost...size (although probably not weight, due to the fat/muscle density differences) while eating 3000+ calories/day (I'm 5'2", and at the time was somewhere between 100 and 120lbs), or gained it while eating less than 2000. Diet's important, but with a metabolism like that, and at your age, it's not going to be the most important (until I hit 20, it didn't matter what I ate, I wouldn't gain weight). Just know that it won't last forever, and you should get into decent eating habits sometime in the next 5 years or so.

You need to work the different sets of muscles in the abs, not just the abs as a whole. When you're doing situps, don't just do them straight forward, do sets off to each side. It works specific sets and works them harder. Flutter kicks will kill you very quickly - lay on your back with your hands under your butt (you don't have to do this part, but it makes it work better, or has for me, helps with balance), lift your feet about 6 inches off the floor, and just do little flutter kicks, like you were swimming. I have yet to find an ab workout as painful and effective.

If you can find a copy of "The Official Naval Academy Workout" or any of the prep books for getting into Navy, that's how I prepared, and I went in with a 6 pack. And most of the exercises that it uses don't involve any equipment, so they're easy to do at home or wherever.

Fish is a good start, Omega 3's. Just eat healthy, no real diet if you have a good metabolism. Use olive oil instead of butter, get in plenty of carbs but don't over due it. Yogurts, fruits, veggies without to much sugar or salts. Use sea salt, it's better for ya. I think your on the right track. Cardio exercise will help keep any x-tra fat off.

dude. I'm a personal trainer just stay in that gym.

if you're skinny don't do cardio. just build up that muscle mass. you also might be to young

Once you gain some body mass, which happens when you reach a certain age, muscle building will be no problem.

If you have been working on your abs with the routine you do, you will only get hard abs. To get a 6-pack you need to burn the fat.

One way to do that is to build muscle which you are doing. Remember to vary up your ab exercises since your stomach is very adaptable. Also eat a meal or protein shake within 30 minutes of finishing up. As Schneiderman says, there are more to a 6pack than just abs.

Second: You have to burn more calories than you take in. So you have to change your diet to get all the necessary nutrients while cutting back on the calories. Also cut down on the carbs. Only have carbs for breakfast and a little for lunch if you can't avoid it. Drink lots of water as that will make you feel full and will cause you to eat less.

Third: You need to run everyday. Running burns calories. Combined with exercise, you should have negative calories by the end of the day.

This is my kind of question.
4,000 calories is way too much. the average person needs 2000, with the average male athlete needing approximately 2500.
im 6'3 and 170 pounds and I don't need anywhere near 4000.
try to balance your diet out. that means getting the appropriate amounts of protein, carbohydrates, water, minerals etc etc
try to eat fruits and vegetables.

if you are hungry through out the day, eat more, less often. When you eat less but more often, your body burns energy more efficiently. Just snack on something. eat about 5 meals a day.

as for the protein, you really don't need that much more than you think. you need about 1.4-1.7 grams of protein a day more than the average person for each kilogram you weigh. Since you are 140 lbs, you'll probably only need at max 20 grams more than the average person, which is like 2 slices of bologna.

the exercises are pretty legit. try planks, the roman chair (its where you have your arms on these padds and you are in the air and you lift your legs), sit ups, reverse sit ups, scissors,
work your obliques too. 6-pack is not just abs.
try to stand up straight also. legs should be straight, knees tight (but not completely locked),

do you have access to a physioball? there are some routines with that that are actually pretty good.

also, you want to take in an adequate amount of water. water is important for many things.

another important part of getting this six pack, is to exercise. not just strength training though, like you are doing with the sit ups and the curl ups etc. but by cardio. get your heart rate up for periods at a time. make yourself sweat. do at least 30 minutes a day.

as a note, six packs are not always great. they are just appearance. they are not a measure of how much the actual muscles can do.

carbohydrates are good. and not all of them are the same. carbohydrates help with how much water is stored in the body.
carbohydrates are the main source of fuel in the body. it is directly burned into fuel. Simple carbohydrates is broken down really easily. whereas complex carbohydrates take a longer time and give more energy.