If your mind is totally made up to do this, then you can! Our daughter, age 14, has lost 30 pounds in 7 months. We totally changed our way of eating and have seen success. It is a very slow process, but it does come off. She was a bit discouraged at first because it is a slow process. However, she is now very excited and feels so much better. She never wants to go back to the old way of eating.
So, it can work but your mind must be made up to make it work.