To avoid excess skin you would want to lose weight as slowly and gradually as possible, maintain good nutrition, and maintain strength through weight training or other weight bearing exercise. There can be considerable muscle loss when there is large weight loss without strength training, and this can contribute to loose skin. I am figuring you want to get down to about 110 lbs? If that is the case give yourself 2 years to do it. Sounds like a long time but you will be healthier in the long run.
Bob Stein, Ph.D.
Lancaster, PA