I eat junk food but do sports,my legs have gotten big i think it's part muscle and fat, iwant them skinnier.

okay...first of all if you want to become "skinner", you have to keep this in mind. Your body's statistics (weight,height,muscle m...etc) weight heavily on genetics. To gain more muscle m and loose weight aka "skinner", you have to watch diet and exercise. Not one,but both. To loose weight you do aerobic (cardio, running, swimming...etc) to gain muscle do anaerobic (life weights,but keep your heart rate lower than "cardio heart level"). You will notice at first, your leg muscles get bigger, then you pectoral muscles & arms. Finally, your abdomen area (abs,stomach,gut...etc) get smaller. SO, if you want a 6 pack, its not just doing 600 sit ups a day. Its about reducing your body fat in your stomach area. So, a 6 pack translates into somewhere between 9-12% body fat. I recommend onto of reading all of this, you take in proteins offering lean fat , such as turkey and taking in more linoleic acid. I take in linoleic acid in almost everyday, and it has been proven and I find has helped me, you can get it from olives, thats where I get it. Finally, take a mulivitamin. Hope this helped you