There are two things you need to be able to do:
- You will probably need to learn how to eat appropriately.
- You will also need to add some physical activity to your life.
The problem is that we don't know jack shit about food and nutrition! We grow up bombarded with marketing that extols the virtues of all the processed crap sitting on the shelves of our supermarkets and corner stores.
Your homework is to open your eyes, stop being a blind consumer, and figure out what exactly real food is. It's not a chip, a cake, a cookie, a chocolate bar, or anything that claims to be fast food. It sure as hell isn't sugar water in a bottle or can.
Go ahead and figure out how to pull your head out of your nutritionally challenged fat ass while I work on another beginner level post. I'll even give you a free hint -- it's easier to eat better if you don't bring crappy shit home from the store in the first place.