Unless you want to be an adult contestant on the Biggest Loser, you will change your diet. Start with asking your mom if you have her permission to throw out all junk food. In the mean time change your diet little by little. Go online and read up on good nutrition. I promise you by the time your 30 the poor eating habits will catch up to you.....the really bad part is the eating habits you have now will be so ingrained that you will have a very hard time changing. If you don't change now.
Most of us eat too much junk food. Next time, ask yourself what would be a better thing to eat and then go get that. Keep more healthful snacks around; ask your parents to help by buying good food; help them with the grocery shopping.