Fasting is a very unhealthy way to lose weight. It causes an increase in cortisol and adrenaline (and in this way can lead to an increase in insulin when you start eating again) and causes your metabolism to slow down and your body to store fat as a self-preservation mechanism. You will also lose too much muscle. Fasting can have health benefits, but as a tool for weight loss it is possibly the worst. It can also easily lead to beingeing (it does with me). I have caused my self serious and long-term metabolic damage by fasting too much (cortisol, adrenaline, insulin, DHEA and testosterone).
Just eat healthy food (lots of veggies!) and exercise moderately. This is the best way to control your weight. And DON'T OBSESS ABOUT IT. This is my problem and the main root of my eating disorder. All I think about is weight and fat and it's very unhealthy and the cause of great misery. There are more important things in life - friends, work, God, love. Just be healthy.