Living with PCOS: why the usual advice keeps failing you

PCOS affects roughly one in ten women of reproductive age. It is diagnosed on the Rotterdam criteria — two of three from irregular or absent ovulation, clinical or biochemical signs of raised androgens, and polycystic ovarian morphology on ultrasound — after other causes have been excluded.

Why weight behaves differently

• Insulin resistance is present in a large proportion of women with PCOS, including many with a normal BMI. Higher circulating insulin promotes fat storage and makes fat release harder.
• Raised insulin drives ovarian androgen production, which in turn favours central fat distribution.
• Appetite regulation is often altered, with reports of reduced post-meal fullness.
• The cycle is self-reinforcing: weight gain worsens insulin resistance, which worsens the hormonal picture.

The practical implication is that a plan built purely around eating less tends to underperform. Plans built around insulin sensitivity tend to do better.

What the evidence supports

Weight change of 5–10%

A modest, sustained reduction can restore ovulation in a meaningful proportion of women, improve cycle regularity and reduce androgen symptoms. It is one of the few interventions with effects across every domain of the condition.

Resistance training

Muscle is the main site of glucose disposal. Two or three sessions a week improve insulin sensitivity independently of weight change — which matters when the scale is stubborn.

Dietary pattern over dietary rules

No single diet is proven superior for PCOS. Lower glycaemic-load eating, adequate protein and a Mediterranean-style pattern all perform well. Adherence is the deciding variable, so choose the pattern you can actually keep.

Metformin, where indicated

Metformin improves insulin sensitivity and can help cycle regularity. It is a prescription medicine requiring assessment and monitoring, and it is not a weight-loss drug — the average effect on weight is modest.

Inositol

Myo-inositol has reasonable evidence for improving insulin and ovulatory measures in PCOS, and it is well tolerated. Discuss it with a clinician rather than adding it blind, particularly if you are already on treatment.

Tests worth having

Getting assessed in Ireland

An online GP consultation is a reasonable starting point: we can take a full history, review your cycle pattern and symptoms, arrange the blood tests above through a local phlebotomy service, and refer for pelvic ultrasound where it is indicated. What we cannot do remotely is the ultrasound or the physical examination, so expect a hybrid pathway rather than an entirely online one.

Share this guide