Weight Loss and Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is one of the most common hormonal conditions in women of reproductive age, affecting approximately 8–13% of women globally. It is characterised by irregular periods, elevated androgen levels (which can cause acne, excess hair growth, and hair thinning), and polycystic ovaries on ultrasound. Many women with PCOS also struggle with weight gain and find it harder to lose weight than women without the condition.

Why does PCOS make weight management harder?

The central mechanism is insulin resistance. In women with PCOS, cells respond less effectively to insulin, so the pancreas produces more of it to compensate. Elevated insulin levels stimulate the ovaries to produce excess androgens, which disrupts ovulation and contributes to the hormonal imbalances that define PCOS.

High insulin levels also promote fat storage — particularly around the abdomen — and increase appetite by affecting hunger-regulating hormones. This creates a cycle in which weight gain worsens insulin resistance, which in turn makes further weight gain more likely.

What are the health risks of PCOS and excess weight together?

• Type 2 diabetes — women with PCOS have a four to seven times higher risk of developing type 2 diabetes than women without the condition
• Cardiovascular disease — PCOS is associated with dyslipidaemia, hypertension, and endothelial dysfunction
• Endometrial cancer — irregular or absent periods mean the endometrium is not shed regularly, increasing cancer risk
• Obstructive sleep apnoea — more common in women with PCOS, particularly those with central obesity
• Mental health — rates of anxiety and depression are significantly higher in women with PCOS

Does weight loss improve PCOS?

Yes — even modest weight loss has a significant impact. A 2019 systematic review in Human Reproduction Update found that weight loss of 5–10% of body weight improved menstrual regularity, reduced androgen levels, improved insulin sensitivity, and increased the likelihood of spontaneous ovulation in women with PCOS.

Weight loss also improves fertility outcomes. Studies show that women with PCOS who lose weight before fertility treatment have higher ovulation rates and better pregnancy outcomes than those who do not.

What approach works best?

A low glycaemic index (GI) diet — which reduces blood glucose spikes and therefore insulin demand — is particularly well-suited to women with PCOS. Regular physical activity improves insulin sensitivity independently of weight loss. A doctor-led programme can tailor recommendations to your individual hormonal profile and health goals.

If you have PCOS and are struggling with your weight, speak to the Weight Loss Wales team for a personalised consultation.