Keto and PCOS: What a 2024 Review of the Trials Found

Polycystic ovary syndrome affects a great many women, and one of its central threads is insulin resistance: the body struggles to handle carbohydrate efficiently, insulin runs high, and that in turn nudges the ovaries to produce more male-type hormones than they should. Because a ketogenic diet directly lowers the carbohydrate the body has to deal with, researchers have wondered whether it might help with PCOS specifically. A 2024 review gives the most useful answer so far.

What was studied

Xing and colleagues, writing in Food and Nutrition Research, carried out a systematic review and meta-analysis. They searched the literature for randomised controlled trials testing ketogenic diets in women with PCOS who were overweight or obese, found eleven that met their standards, and pooled the results, covering 426 women in total. Combining trials this way smooths out the quirks of any single small study and gives a clearer overall signal.

The weight and body composition results

The physical changes were sizeable. Pooled across the trials, women following a ketogenic diet lost on average around 9 kilograms of body weight, dropped close to 3 points of BMI, took more than 7 centimetres off their waist, and lost over 5 kilograms of fat mass. Every one of these results was statistically significant, meaning they are very unlikely to be chance. For a condition where excess weight and central fat tend to worsen the whole picture, those are meaningful numbers.

The part that matters most for PCOS: the hormones

Weight loss alone would be useful, but the review found something more specific to PCOS. The ketogenic diet was associated with lower levels of androgens, the male-type hormones that drive several PCOS symptoms, alongside higher levels of sex hormone binding globulin, a protein that mops up excess free testosterone, and improved insulin sensitivity. That cluster matters because it targets the hormonal machinery of the syndrome, not just the bathroom scales. Lower androgens and better insulin handling are exactly the direction women with PCOS are usually trying to move in.

Where the evidence is thin

This is promising, and it is also early. The review’s authors were candid about the weaknesses, and they are worth repeating. Most of the trials were short, generally under six months, so we cannot say much about what happens over years. There was meaningful variation between studies in who took part and how the diet was run, which makes the pooled figures a touch fuzzier. And by the nature of a diet you cannot blind people to which one they are on, which always leaves a little room for expectation to colour results. None of this cancels the findings, but it means they are a strong lead rather than the last word.

What it suggests in practice

For a woman with PCOS who is carrying extra weight, the research points to keto being a reasonable option to consider and discuss, with a fair expectation of weight loss and, more interestingly, some movement in the hormones that underlie the condition. The insulin-resistance angle is the thread that ties it together, and it is the same reason low-carbohydrate eating keeps coming up in PCOS conversations.

A couple of practical notes. Keto can affect the menstrual cycle, sometimes settling it and sometimes disrupting it at first, so it is worth tracking. If you are trying to conceive, are pregnant, or have other health conditions, this is firmly a conversation to have with your doctor before starting rather than a thing to try alone. And as with anyone new to the diet, getting electrolytes right early makes the first weeks far more bearable, while our beginners guide covers the basics of setting it up sensibly.

The bottom line

A 2024 meta-analysis of eleven trials in 426 women found that the ketogenic diet produced significant weight and fat loss in PCOS and, notably, moved the underlying hormones in a helpful direction by lowering androgens and improving insulin sensitivity. The studies were mostly short, so the long-term picture is still open, but as a starting point the evidence is genuinely encouraging.

This is general information about the ketogenic diet, not medical advice. PCOS is a medical condition; if you have it, are trying to conceive, or are pregnant, speak to a doctor or dietitian before making a big change to how you eat.

Source: Xing et al. Effects of ketogenic diet on weight loss parameters among obese or overweight patients with polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials. Food and Nutrition Research. 2024. Read it here.