How to potentially reverse PCOS with low carb

Polycystic ovary syndrome (PCOS) is a common disorder that affects 4-20% of women of childbearing age worldwide, and its incidence appears to be increasing over time.1 Beyond menstrual problems and other physical signs and symptoms, it’s a leading cause of infertility.2
Fortunately, there’s a potentially effective lifestyle treatment available: a low carb diet.

Signs and symptoms

Here are the most common signs and symptoms associated with PCOS:


  • Menstrual irregularities like irregular, skipped or heavy periods
  • Inability to get pregnant
  • Acne
  • Excess facial and body hair, showing up in a male pattern (including the upper lip, chin, and chest)3
  • Obesity

Causes and treatment

The underlying causes of PCOS are complex and have been debated for decades. However, it is clear that the vast majority of women with PCOS have what is known as functional ovarian hyperandrogenism. This means that the ovaries are extraordinarily sensitive to signals that lead them to overproduce androgens (hormones like testosterone with “male” effects).4

This, of course, also increases the risk of developing type 2 diabetes. Given that low-carbohydrate diets have been proven very effective for treating insulin resistance, obesity, and type 2 diabetes, it makes sense that they would also be useful for treating PCOS.5

In fact, any lifestyle intervention that results in weight loss or pharmacologic intervention that enhances insulin sensitivity may improve the features of PCOS.6

But, given that low carb diets directly address insulin resistance — beyond any effect on weight — we believe that they are a particularly effective tool in the toolkit for PCOS. There is now a growing body of research that supports this contention:

  • In 2005, researchers followed 11 women with PCOS as they followed a keto diet for six months. The five women who completed the study lost weight and improved some of their hormonal markers. What’s more, two of the women became pregnant during the study, despite previous infertility problems.7
  • A 2013 study found that even a very modest reduction in carbohydrates (41% of calories) can lead to significant improvements in hormones and other metabolic risk factors, even in the absence of weight loss.8
  • A 2017 systematic review of clinical trials found that low carb diets tend to “reduce circulating insulin levels, improve hormonal imbalance and resume ovulation to improve pregnancy rates.9 A 2019 meta-analysis of randomized trials showed similar findings, concluding “proper control of carbohydrate intake provides beneficial effects on some aspects of PCOS and may represent one of the important interventions improving the clinical symptoms of affected patients.”10
  • In a 2020 study, 14 women with PCOS followed a ketogenic Mediterranean diet for 12 weeks. By the end of the study, they achieved lower blood glucose and insulin levels, improvements in reproductive hormone levels and function, reduction of heart disease risk factors, and an average weight loss of 20 pounds (9.4 kg).11
  • A 2021 study of women with PCOS, obesity, and fatty liver randomized the participants to a ketogenic diet or conventional pharmacologic therapy. Those who received the ketogenic diet demonstrated better decreases in blood sugar and weight, and greater improvement in fatty liver.12
  • Finally, a 2021 systematic review of RCTs concluded that dietary interventions improve PCOS symptoms, and low carb is likely superior for fertility and restoring normal menstruation.13

Reversing PCOS and getting pregnant

There are several stories of women reversing their PCOS symptoms and in some cases suddenly getting pregnant after going low carb.14 It can sometimes feel like a miracle. Of course, it’s not that kind of miracle, but it’s still pretty impressive.

This is simple biology. Cutting back on carbs can help with weight loss, lower insulin levels, and reverse insulin resistance, which may help to balance the hormonal system. This can enable ovulation and a normal menstrual cycle, in addition to improving or eliminating other symptoms.15

While the stories of these women can be inspirational, it’s important to remember that a collection of anecdotes does not equate with scientific evidence:

  • 'I am the absolute happiest I have ever been. Ever.'
  • Keto and intermittent fasting: 'I am completely blown away by the changes'
  • "Within three months of starting a well-formulated ketogenic diet, all flares were gone!"

All PCOS success stories

Professional experience

Some health care professionals have also found that carb restriction can be incredibly effective for helping people with PCOS reverse their disease and get pregnant.16 This includes a group of Australian dietitians that we previously wrote about.

Fertility specialist Dr. Michael Fox has more than a decade of experience helping patients with PCOS and infertility, using a low carb diet.

Dr. Fox found that compared to only using drugs, adding a low carb diet for PCOS patients increased their chance of pregnancy from 45% to over 90%!17

Dr. Michael Fox can be contacted at the Jacksonville Center for Reproductive Medicine.

More about PCOS and keto

Get started

Do you want to try reversing your PCOS using low carb? Try our members-only personalized meal planner service, or use our beginner’s low carb guide.


More benefits of low carb

Why should you consider eating fewer carbs? There are many potential benefits, at all ages (although there’s hardly ever a reason for healthy kids to do a strict low carb diet).

Here are some of the main benefits, and how to adapt a low carb diet for your specific needs, to maximize the positive effects on your health.


  1. Journal of Human Reproductive Sciences 2020: The prevalence of polycystic ovary syndrome: a brief systematic review [systematic review of observational studies; weak evidence]

    The following study demonstrated an increased incidence of PCOS between 2007 and 2017:

    Human Reproduction 2021: Measuring the global disease burden of polycystic ovary syndrome in 194 countries: Global Burden of Disease Study 2017 [observational study, weak evidence]

  2. American Diabetes Association Diabetes Spectrum 2015: The role of polycystic ovary syndrome in reproductive and metabolic health: overview and approaches for treatment [overview article; ungraded]

  3. The likely reason is both an excess of male hormones and increased sensitivity to these hormones. These hormonal disturbances may also result in a deepening of the voice and male-pattern baldness.

    Current Pharmaceutical Design 2016: Hirsutism in polycystic ovary syndrome: pathophysiology and management[overview article; ungraded]

  4. Current Opinion in Pediatrics 2020: Current concepts of polycystic ovary syndrome pathogenesis [overview article; ungraded]

  5. Journal of Diabetes and Its Complications 2015: Effects of a high-protein/low carbohydrate versus a standard hypocaloric diet on adipocytokine levels and insulin resistance in obese patients along 9 months [randomized trial; moderate evidence]

    Nutrition Journal 2010: Changes in weight loss, body composition and cardiovascular disease risk after altering macronutrient distributions during a regular exercise program in obese women [randomized trial; moderate evidence]

    Lipids 2009: Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet [randomized trial; moderate evidence]

    Frontiers in Endocrinology 2019: Long-term effects of a novel continuous remote care intervention including nutritional ketosis for the management of type 2 diabetes: a 2-year non-randomized clinical trial [non-randomized study; weak evidence]

  6. Cochrane Review 2011: Lifestyle changes in women with polycystic ovary syndrome [systematic review of randomized trials; strong evidence]

    Journal of Clinical Endocrinology and metabolism 2015: Randomized Controlled Trial of Preconception Interventions in Infertile Women With Polycystic Ovary Syndrome [moderate evidence]

    Medical Journal of Austrailia 2011: Assessment and management of polycystic ovary syndrome: summary of an evidence-based guideline [overview article; ungraded]

  7. Nutrition & Metabolism: The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: A pilot study [non-controlled study; weak evidence]

  8. These two publications are both from the same study:

    Clinical Endocrinology 2013: Favourable metabolic effects of a eucaloric lower-carbohydrate diet in women with PCOS [randomized crossover trial; moderate evidence]

    Metabolism 2014: Effects of a eucaloric reduced-carbohydrate diet on body composition and fat distribution in women with PCOS [randomized crossover trial; moderate evidence]

  9. Nutrients 2017: The effect of low carbohydrate diets on fertility hormones and outcomes in overweight and obese women: a systematic review [systematic review of randomized and non-randomized trials; moderate evidence]

  10. International Journal of Endocrinology 2019: The Effect of Low Carbohydrate Diet on Polycystic Ovary Syndrome: A Meta-Analysis of Randomized Controlled Trials [strong evidence]

  11. Journal of Translational Medicine 2020: Effects of a ketogenic diet in overweight women with polycystic ovary syndrome [non-controlled study; weak evidence]

  12. Journal of Obstetrics and Gynaecology Research 2021: Ketogenic diet in women with polycystic ovary syndrome and liver dysfunction who are obese: A randomized, open-label, parallel-group, controlled pilot trial [moderate evidence]

  13. Frontiers in Endocrinology 2021: Dietary modification for reproductive health in women with polycystic ovary syndrome: A systematic review and meta-analysis [strong evidence]

  14. [anecdotal reports; very weak evidence]

  15. AACE Clinical Case Reports 2018: A ketogenic diet may restore fertility in women with polycystic ovary syndrome: a case series [case series; weak evidence]

  16. [clinical experience of low carb clinicians; weak evidence]

  17. [single clinician experience; very weak evidence]