At 16 years old you shoud take your well being seriously, young people can do far more harm to themselves by nutritional lapses than older fully developed adults would suffer.
Certainly it is a good idea to try and eat healthily and adapt to a healthier lifestyle... and if you do that then you are certain to acheive sustainable weight loss.
You may be wanting a 'quick start' but truthfully you've been getting fatter and being fat for a good while now.. so I can't see the point in needing a sudden change.. least of all an unhealthy one that teaches you nothing.
But... if you decided to do single day water fasts even as often as once a week, I don't think that would do you any harm at all, and probably a huge deal of benefit... especially if you make sure your pre and post fast days are supremely healthy with heaps of vegetables, high quality protein and top grade carbs.
Good luck, and remember the real objective is to become healthier (slimming is a natural side product of healthy living)... if you just try and get slimmer most likely you will fail to get any healthier, and be unable to maintain any weight lost.