Welcome, Ryan.
My #1 advice is cut all the crap out of your diet. I recall as a teen the stuff I ate, and if you're anywhere similar, that would help you enormously. No more soda, chips or any junk food, no fast food, avoid processed foods period, avoid all products containing sugar or corn syrup. Avoid wheat products. I know as a teen you're at the mercy of what your parents buy and bring into the house, so hopefully they are at least somewhat health conscious. And you can always show them what you learn as you go through this journey- maybe you'll end up helping them improve their health as you improve yours!
I urge you to look at this website:
MarksDailyApple. I learned more from that one website than any other, and it made a lasting impression on me. It will explain exactly why you need to avoid processed foods and many grains. If you want to know why you need to avoid sugary foods/drinks, watch
this. It's long - an hour and a half- but it is life changing. I have never looked at sugar the same way, and it completely changed how I saw things in the grocery store.
Welcome to 3FC, and good luck!