I have successfully stopped drinking Cola drinks, Ice Tea, and anything with high amounts of sugar or things with aspartame. The only drinks I drink now is pure apple juice, and water. With the exceptional refreshing drink during the summer, I'll be drinking lemonade except with organic brown sugar. I feel so much better now than I have been a few months ago.
I switched my food diet to more fruits, and for sandwiches, I have organic peanut butter and jelly. (I need to find organic jelly with less sugar).
The only thing now that needs to change is the chicken, turkey, or meat that I eat. I can't at the moment because my parents can't bother to get raw duck, chicken, turkey or steak from organic food stores. There excuse 'more expensive and they are all the same'. No matter, I'll feed myself organic food when I turn 18 and move out. When I go out to eat hamburgers, (I need to gain more weight), I go to the Byron's here in London. They serve lean cut beef burgers and they don't use MSG as far as I can tell.
I don't eat anymore nutri-grain bars (they are quite bad), and I don't eat any more junk food. I never knew I had strong willpower. Whenever I come across junk food, my body reacts and forces me to stay away from them. It's second nature to me now.
tl;dr - no more junk food, or sugary drinks/foods.