Gynaecology · 7 min read · July 2026
PCOS: why the diet advice is the treatment, not an afterthought
PCOS is a metabolic condition with gynaecological consequences. Tablets can regulate a cycle for as long as they are taken; insulin sensitivity is what changes the underlying picture, and that is largely won on diet, activity and sleep.
What the diagnosis actually rests on
Two of three: irregular or absent ovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on scan — after thyroid disease, raised prolactin and late-onset adrenal hyperplasia have been excluded. A scan alone does not make the diagnosis, and many women are told they have PCOS on the strength of one ultrasound.
The five to ten per cent that matters
A weight loss of five to ten per cent of body weight restores ovulation in a substantial proportion of women with PCOS and a raised BMI. That is four to seven kilograms for many patients — a target that is reachable, unlike the number most women are told to aim for.
What to change first
Protein at breakfast, a cap on refined carbohydrate at the evening meal, and one hundred and fifty minutes of activity a week with two sessions of resistance work. Sleep of less than six hours worsens insulin resistance measurably; it is treated as part of the plan here rather than as lifestyle advice.
Where medication fits
Cycle regulation, insulin sensitisation or ovulation induction are prescribed for a defined period with a review date, not indefinitely. If you are trying to conceive, the sequence is different and is planned at the visit.
When to come in
- Cycles longer than 35 days, or periods that have stopped
- Acne, hair loss or excess facial hair
- Difficulty conceiving after twelve months