We didn't have fast food when I was young :-) McDonalds wasn't around until I was getting out of high school and the one "closest" to me was a 45 minute drive (if you can imagine that!) and a "treat" to go to!

Does your mother make dinner? Do you eat that? I assume that has meat, veggies and carbs, is probably a "good" dinner. I'd start taking your lunch 2-3 days a week and pack some string cheese, fruits, maybe carrots/celery and a little ranch dressing dip; get some more dairy, fruits and veggies into your diet instead of junk food.

Eat a real breakfast. It will make you less hungry for the junk later in the day, keep you filled up some. A good cereal (old fashioned like Cheerios or Frosted Shredded Wheat

No, gatorade and sports drinks are perhaps even worse than some sodas. Drink a bottle of water every now and then and, if you can stand it, a glass/carton of milk? Nothing replaces the water you need besides "real", straight water. That's one habit I would have gotten into sooner if I could have is drinking water. We didn't have as many sodas though either back in the stone age :-) My mother only bought my brothers and me 2 Cokes apiece per week.

An "easy" healthy diet to follow is the DASH plan. You can download that free here: http://www.cardioconnection.org/media/pdf/new_dash.pdf