From a male perspective I can definitely say the 5:2 diet works, if you give it a genuine try. Ive lost 18kg (40 lbs) in one year. If your pcos stems from insulin levels that are too high then the diet should help. Perhaps see your doctor and get some bloods taken to see where you are now. Then go on the diet and get them measured 3-6 months from now. Id cut out all foods with sugar in them, which is just about anything that comes in processed food packaging.