Fasting is the best way to cure PCOS. You can lose 1lb per day on average.
The only advice I can give you is to stay warm, nothing but drink warm water, rest and have happy thoughts. No mouth washes, chewing gum, vitamins or partial foods.
Muscle does not get wasted till you go in starvation. Body has a unique way of discriminating in what to use for energy.
Post fast diet will be equally important to stay healthy and disease free.