Keto trimmed waists in PCOS, but mind-body exercise won on blood sugar

Women with polycystic ovary syndrome face an elevated long-term risk of type 2 diabetes and cardiovascular disease, driven largely by a cluster of cardiometabolic abnormalities such as insulin resistance, unfavourable blood fats and raised blood pressure. Lifestyle change, mainly exercise and diet, is the first line of management, yet nobody has been sure which specific approach works best for which outcome. Individual trials usually test one intervention against one control, so they cannot say whether keto beats a low-fat diet or whether HIIT beats yoga. This review set out to compare the options against each other and to explore whether the dose of exercise changes the benefit.

The researchers searched five databases up to June 2026 for randomised trials of lifestyle interventions in women with PCOS, excluding drug studies and interventions shorter than 2 weeks. After exclusions, 43 studies with 2433 participants were included. They used a Bayesian network approach that lets every intervention be compared with every other, even when no trial tested them head to head, across 16 outcomes grouped into five domains: body composition, glucose and insulin regulation, blood lipids, inflammation and blood pressure. Interventions were ranked by probability of being best, risk of bias was formally assessed, and confidence in each estimate was graded.

Within the dietary comparisons, the ketogenic diet reduced waist circumference by 5.74 cm and BMI by 2.61 kg/m² versus control, though each estimate rested on 2 study arms. Within the exercise comparisons, aerobic exercise ranked best for waist to hip ratio and for systolic blood pressure, where it cut readings by 3.49 mmHg. Mind-body exercise ranked best for insulin resistance, fasting glucose, fasting insulin, triglycerides and LDL cholesterol, while HIIT ranked best for raising HDL cholesterol by 0.05 mmol/l. An exercise dose of roughly 480 to 1012 METs·min per week showed the greatest overlap in predicted benefits across outcomes.

This is the broadest head-to-head comparison of lifestyle options in PCOS to date, and it extends earlier evidence that exercise and diet both help by suggesting the benefits are split across approaches rather than owned by one. The dose analysis, pointing to moderate-to-vigorous sessions of around 60 minutes, 3 times a week for 13 to 17 weeks for lipid outcomes, is a step towards actual prescription. The major complication is that the certainty of evidence was rated low or very low throughout, several estimates rest on only 2 or 3 study arms, and the rankings could easily reshuffle as larger trials arrive.

For a woman managing PCOS, the picture this paints is of a menu rather than a single answer. Dietary change, and the ketogenic diet in particular within these trials, moved the measures tied to body size, while exercise moved the measures tied to blood sugar, blood fats and blood pressure, with different styles leading on different outcomes. That is a reason to think the choice between HIIT, aerobic work and mind-body practice may matter less than doing enough of something consistently. Given how uncertain the underlying evidence is, it is information for a conversation with a clinician, not a plan in itself.