Sometimes when you lose a lot of weight you are left with extra skin because it stretched and grew to accommodate the extra fat.
If you have lost a large amount of fat you know what I’m talking about, you can replace it with muscle which is the best way. Most of the extra skin goes back to normal size but it depends on age and it takes time. If your weight loss is slower your skin may keep up with your new body. Natural is best because it’s also a learning lesson of how to eat and getting in a routine of eating habits and exercise. Surgery is the fastest to tighten your skin up but can be costly. As I said earlier age is a factor, I lost over 50 lbs myself before and I had loose skin I gave it time but I am the type of person who gets gratification from doing it myself. If you take the time to lose the weight take the time to finish the job. Having lose skin from weight loss is a badge of honor for your hard work.