You could try going on a juicing diet. Where you drink water and use a juicer to juice fruits and vegetables. Its obviously very healthy for you and would help you lose weight. My mother went on a fast ats lost a decent amount of weight she only drank water and used little cubes of beef and chicken stock for flavor. I believe if you keep your belly full with water you won't be hungry. Good luck dearest!
At 15, your body is not fully developed, so crash/fad diets are the worst thing you can do. You simply have to eat healthy - plenty of veggies, lean protein, etc.
You should ask to have your thyroid tested to make sure it's working properly. Iron is necessary for proper thyroid function and your thyroid controls metabolism. If you're deficient in iron, you may also be deficient in thyroid hormones.
Are you making sure you're getting adequate exercise?
I can honestly say crash diets are not that great for long term weight loss. I have always been quite a large child, whilst all my siblings were rather tiny and I struggled so much with Weight but what I felt worked best was eating lots of protein and lean meats with lots of vegetables. I also found green tea with lemon and raspberry tea quite effective. It takes time but you'll get there.
Crash diets are not the way to go hun. Believe me. You just need to cut portion sizes and lit your calorie intake. Why not ask your Gp to refer you to a dietician. They can help you with meal plans and nutritional information. Untill your referal I foumd a great help is to use a side plate for dinner as it creates the illusion that your eating more than you are. Limit your carb intake but dont cut it out completely as you still need carbs to create slow burnimg sugars. Steer clear of fizzy drinks including diet drinks as they can make you feel hungry. And limit sweet and crisp intake to 1 treatper week. Losing 1kg a week is normal and healthy and you are less likely to regain the weight when you lose it slowly. Good luck hun x