You're 16. Your bones and muscles are still growing. It's extremely important that you not starve your body ever (but particularly at this time). Strict dieting will make you lose weight, but a high proportion of that weight is muscle - that's why you feel weak and can't perform sports as well. When you lose muscle, you lose metabolically active tissue. Muscle burns calories, body fat does not.
A body that thinks it's starving will start to drop muscle and hold onto fat in an effort to survive, since fat doesn't require calories. The more muscle you have, the more calories you need. Losing muscle makes it easier to gain more fat. The reason most crash diets fail is because they focus on weight loss rather than bodyfat loss - they kill the muscle and kill the metabolism. A pound of muscle takes up less space than a pound of fat. That's why a lean muscular guy will weigh (and can eat) more than just a skinny guy of approx the same body measurements.
It make take some time to retrain your metabolism, but it can be done. (I'm a 20 vet of eating disorders, and believe me, you do NOT want to go down that road!) Small frequent meals every 3-4 hours will keep your blood sugar stable and your metabolic fires burning. Each meal should contain some protein. When you don't eat for awhile, the fire goes out, and the body tends to store more bodyfat the next time you eat because it thinks you're going to starve it again.
A body that thinks it's starving will start to drop muscle and hold onto fat in an effort to survive, since fat doesn't require calories. The more muscle you have, the more calories you need. Losing muscle makes it easier to gain more fat. The reason most crash diets fail is because they focus on weight loss rather than bodyfat loss - they kill the muscle and kill the metabolism. A pound of muscle takes up less space than a pound of fat. That's why a lean muscular guy will weigh (and can eat) more than just a skinny guy of approx the same body measurements.
It make take some time to retrain your metabolism, but it can be done. (I'm a 20 vet of eating disorders, and believe me, you do NOT want to go down that road!) Small frequent meals every 3-4 hours will keep your blood sugar stable and your metabolic fires burning. Each meal should contain some protein. When you don't eat for awhile, the fire goes out, and the body tends to store more bodyfat the next time you eat because it thinks you're going to starve it again.