I'm 28 and have just had polycystic ovary syndrome (PCOS) diagnosed. I'm about two stone overweight and have been told that losing this will help. Is this true, and what is the best diet to follow? I have terrible sugar cravings, am really moody, have oily skin and feel shattered all the time.

These are common symptoms of PCOS, along with an increased risk of infertility and miscarriage, oily skin, excess facial hair, poor sleep patterns, feeling dizzy on standing and rapid weight gain.

The exact cause of PCOS is not known but has been linked to lifestyle and, in some cases, genetic factors. Carrying excess weight is implicated because eating more food than we need forces our pancreas to produce larger-than-normal amounts of the hormone insulin (to clear the blood of high levels of sugar deposited after large meals and lots of snacks).

Extra insulin seems to reduce production of female sex hormones while increasing production of the male sex hormone testosterone, which can trigger hair growth, oily skin and a disturbed menstrual pattern.

Losing even 5 per cent of your weight has been found to reduce insulin levels, which in turn can rebalance sex hormones and may help to restore menstruation and improve facial hair and acne. Shedding pounds by eating carbohydrate foods that are digested slowly (a “low glycaemic index” or low GI diet) and do not trigger an insulin surge appears to be extra effective at helping to relieve symptoms.

This means swapping standard processed breakfast cereals, toast and marmalade or a croissant start to the day to porridge, sugar-free muesli, granary bread and poached or boiled eggs or a fruit salad with yoghurt. At lunch and dinner it means opting for pasta, pitta bread and tortilla wraps, sweet potatoes and noodles. These slow-release carbohydrates can be enjoyed with lean meats and chicken, fish, eggs, milk, pulses or Quorn for protein and plenty of vegetables and a few servings of fruit each day. Not only might eating in this way help to rebalance your hormones, it should help to make you feel less hungry and reduce sugar cravings so that you feel more in control. Dietitians say that it is not uncommon for PCOS to go hand-in-hand with binge eating, especially on quickly digested high-GI carbohydrates which cause blood sugar levels to escalate.

Biscuits, cakes, toast and sweets are often turned to as comfort food because of the sugar rush they give. But the relief is short term because as blood sugars soar they trigger the vicious circle of excess testosterone, worsening of symptoms, low energy, mood swings and more cravings which often lead to a further binge.

As energy levels and self-esteem gradually improve, it becomes easier to feel more in charge, to take control and to consider another vital element to improving life with PCOS - exercise.

If you have nutrition questions for Amanda, e-mail her at amandaursell@thetimes.co.uk

Coping with PCOS

The altered hormonal pattern in women with PCOS is thought to lead to a rise in blood pressure and “bad” fats in the blood, so cutting back on saturated fats and salty processed foods is probably wise.

So too is ensuring a regular intake of omega-3 fats. Try oily fish twice a week, an omega-3 supplement or foods fortified with these essential fats.

Take your doctor's advice. They may suggest dietary changes accompanied with a prescription of Metformin (a drug used to treat type 2 diabetes) to help to lower raised blood sugar.

Just 30 minutes of exercise a day can help to lower insulin levels and may help to lift low moods and tiredness.

Chasteberry stimulates production of the female hormone progesterone and helps to restore a regular monthly cycle.

Half a teaspoon a day of ground cinnamon has been found to reduce sugar levels in the blood. Sprinkle on to cappuccinos and stir into yoghurts and fruit.

For further information on PCOS go to www.verity-pcos.org.uk and see The Low GI Guide to Managing PCOS (Hodder Mobius, £7.99) by Dr Jennie Brand-Miller and Professor Nadir R. Farid