It's absolutely true about the diet and exercise. With PCOS, obesity or overweightness will aggravate the situation. It will enhance the estrogen and androgen production in this disorder, which only magnifies the problems of irregular bleeding and excessive hair growth. Some women after losing weight will no longer show signs of PCOS. (These women usually have had no signs of PCOS until after they started to gain weight) That isn't to say that being overweight causes PCOS. I was diagnosed with PCOS at 15 when I was at my slimmest and trimmest.
Hope that helps!!
Rose