When I found out I had PCOS (I was 13), my OBGYN just told me to limit eating breads and excersize 4 or 5 times a week. I went on Atkins for about a year, weighed 120 pounds, and when I got off the diet I immediately gained all of the weight back plus 50. I'm not saying anything is wrong with Atkins, it's actually a pretty fast acting diet and it works. Just make sure if you do it you stay on it, or if you don't want to stay on it, make sure you wean yourself off of it slowly.
Best of luck