I have some questions about the HCG diet?

Ok firstly, i have been on it about a week and a half and i have lost 15 lbs. But I realized i have not been really eating enough meat, is that going to cause me to gain a lot of my weight back? I am only on this round for 3 weeks. Also once I am off the diet for a while, and start eating breads and dairy again, what is stopping me from gaining all the weight back? I read that it re-boots your metabolism is this true??