I'm fasting at 600 calories a day, and I don't feel hungry. Is what I'm doing

[mike f]

healthy? I'm 15 years old (male) and I weigh 278 pounds, I drink water and 3 slim-fasts a day, i work out for 2 hours a day because I really want to lose weight and my doctor recomended a fast (as an afterthought I'm 5 feet 8 inches if it matters). My mom says its fine but ive been seeing all this stuff about how losing a lot of weight too fast is unhealthy. So basicly I'm asking is what I'm doing healthy?