Many women with PCOS gain weight or find it hard to lose. Moderately low carb diets (South Beach or Weight Watchers), and complex carbs instead of simple cards are good: brown rice, whole wheat bread/pasta, less sugars, and more protein. Portion control is also important, paying attention to serving sizes. Exercise is recommended: do weights and cardio at least three times a week: weights increase muscle mass, which burns more calories. Some women lose weight on metformin treatment, too.