Introduction
Polycystic Ovary Syndrome (PCOS) is a prevalent hormonal disorder affecting a significant number of reproductive-age women, with estimates ranging from 6% to 20% depending on the population studied and diagnostic criteria used. This condition often leads to irregular menstrual cycles, weight gain, and insulin resistance, impacting fertility and overall health. In an attempt to manage these symptoms and achieve weight loss, many women with PCOS are turning to the ketogenic (keto) diet-a high-fat, low-carbohydrate eating plan. While the keto diet may offer some benefits, it also presents potential risks that need careful consideration.
What Is the Keto Diet?
The keto diet is characterized by a very low carbohydrate intake, typically less than 50 grams per day, coupled with high-fat consumption. This drastic reduction in carbohydrates forces the body into a metabolic state called ketosis, where it begins to burn fat for energy instead of glucose (sugar). A typical keto diet includes:
- High-fat foods: Avocados, nuts, butter, oils, fatty fish
- Moderate protein: Eggs, chicken, fish
- Very low carbs: Less than 50 grams per day (avoiding bread, rice, fruits, and sugary foods)
The primary goal is to reduce carbohydrate intake to 20-50 grams per day, encouraging the body to produce ketones for energy. This shift in metabolism is associated with various health benefits, particularly for those with metabolic disorders like PCOS. Entering ketosis typically takes 2-4 days of following the diet strictly, though this timeframe can vary.
How the Keto Diet May Affect PCOS
Many women with PCOS struggle with insulin resistance, meaning their bodies don’t respond well to insulin, leading to high blood sugar levels. Since the keto diet reduces carb intake, it may help:
- Lower insulin resistance: By reducing sugar intake, the keto diet can decrease the body's reliance on glucose, allowing the pancreas to produce less insulin and reducing strain on the body.
- Promote weight loss: The keto diet may make it easier to maintain a calorie deficit, which is essential for weight loss. Unlike traditional calorie-restrictive diets, keto emphasizes eating healthy fats, which are more satiating and can reduce the urge to snack between meals.
- Reduce inflammation: The anti-inflammatory properties of certain keto-friendly foods (like fatty fish, nuts, and seeds) may offer additional benefits. Reducing inflammation can positively impact symptoms like acne and fatigue, which are often reported by women with PCOS.
Potential Risks of Keto for PCOS
While the keto diet may offer short-term weight loss benefits for PCOS, its long-term risks-hormonal imbalances, nutrient deficiencies, and gut issues-make it a questionable choice.
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1. Hormonal Imbalance & Irregular Periods
PCOS already disrupts hormones like estrogen and progesterone. The keto diet can further stress the body, leading to:
- Worsened irregular periods (due to extreme calorie restriction)
- Increased cortisol (stress hormone), which may worsen PCOS symptoms
2. Nutrient Deficiencies
Cutting out carbs means missing out on essential nutrients from:
- Fruits & whole grains (fiber, vitamins, antioxidants)
- Dairy & legumes (calcium, magnesium, B vitamins)
This can lead to deficiencies, affecting energy levels and overall health. Since whole grains and fruits are key sources of dietary fiber, constipation can become an issue on the keto diet.
3. Gut Health Problems
A healthy gut is crucial for hormone balance. The keto diet may:
- Reduce fiber intake, leading to constipation and bloating
- Disrupt gut bacteria, worsening PCOS-related inflammation
4. Risk of Disordered Eating
PCOS often causes weight struggles, and extreme diets like keto can lead to:
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- Binge-eating tendencies (due to severe carb restriction)
- An unhealthy relationship with food
5. Long-Term Sustainability Issues
Many women find keto hard to maintain because:
- It’s restrictive and socially challenging
- Sudden weight regain can happen when reintroducing carbs
Healthier Alternatives to Keto for PCOS
Instead of extreme diets, consider these balanced, sustainable approaches:
1. A Low-Glycemic Diet
Focus on foods that slowly release sugar into the bloodstream:
- Whole grains (oats, quinoa, brown rice)
- Fiber-rich veggies (broccoli, spinach, sweet potatoes)
- Lean proteins (chicken, fish, tofu)
- Healthy fats (nuts, olive oil, avocados)
2. Regular Exercise
- Strength training helps improve insulin sensitivity.
- Yoga & walking reduce stress, which is crucial for PCOS.
3. Stress Management
High stress worsens PCOS symptoms. Try:
- Meditation & deep breathing
- Adequate sleep (7-9 hours per night)
4. Supplements (If Needed)
Some supplements may help, but always consult a doctor first:
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- Inositol (improves insulin sensitivity)
- Magnesium (reduces inflammation)
- Omega-3 fatty acids (supports hormone balance)
The Keto Diet and Fertility in Women with PCOS
A recent study shows that women with PCOS who follow the keto diet may see improved fertility, weight loss, and lower testosterone.
Research Findings
Researchers from the Ministry of Health Malaysia in Kuala Lumpur, Malaysia, have found evidence suggesting women with PCOS who follow the ketogenic diet may see improvements in fertility, weight loss, and lower testosterone levels.
For the study, Dr. Khalid and her team analyzed data from seven clinical trials evaluating the effects of the keto diet in women with PCOS. Scientists found women with PCOS who followed the keto diet for at least 45 days experienced significant weight loss, improved reproductive hormone levels, and lowered testosterone levels.
When a person eats carbohydrates, their digestive system breaks it down into sugar called glucose. As glucose enters the bloodstream, the body’s blood sugar levels rise, causing the pancreas to produce insulin. Insulin helps remove the glucose from the bloodstream to feed it to the body’s cells. If a person who is insulin resistant eats carbohydrates, the insulin the pancreas makes is not working properly. This ends up causing too much glucose to remain in the body’s bloodstream and the cells do not get the energy they need.
Previous studies have found that females with PCOS who follow a low carb diet may see improvements in:
- insulin resistance
- testosterone levels
- weight loss and body mass index (BMI)
There are a variety of low carb diets, with the keto diet being one of the most well-known. The keto diet focuses on eating protein and healthy fats, and very little carbohydrates. This ultimately uses up the body’s sugar reserves, causing it to start breaking down body fat for energy.
Expert Opinions
MNT also discussed this study with Dr. G. Thomas Ruiz, OB-GYN lead at MemorialCare Orange Coast Medical Center in Fountain Valley, CA. Dr. Ruiz said he was not surprised by this study’s findings because insulin resistance is common with PCOS.
“I have been telling my patients to go on low carb diets for years,” Dr. Ruiz continued. “My preference is the Mediterranean diet, (but) I have a preference for any diet which is low carb where you do not see increased insulin secretion.”
Still, the keto diet is not for everyone, particularly pregnant people, individuals with certain health conditions like hypothyroidism, or those with an eating disorder.
Study: Ketogenic Diet as Medical Prescription in Women with Polycystic Ovary Syndrome (PCOS)
PCOS is an endocrine condition that affects the ovaries, often leading to various combinations of elevated androgen levels with/or oligo-ovulation or polycystic ovaries. PCOS is also linked to multiple metabolic disorders, including glucose intolerance, type 2 diabetes mellitus, hyperinsulinism, insulin resistance, hypertension, and fatty liver. In the VLCKD, fats provide 90% of calories, with carbohydrates and proteins providing the remaining 10%. This diet is adopted in three stages, beginning with the active stage, followed by the re-education and maintenance phases.
Research shows that body composition and carbohydrate metabolism are involved in PCOS. The current review establishes that weight loss alone is inadequate to improve reproductive function. Other dietary interventions tested in this area include the low GI diet, which might reduce inflammation in PCOS through increased glutathione peroxidase activity, a potent antioxidant molecule. KD allows very restricted calories from carbohydrates, with 70% of calories supplied by fat.
Interestingly, PCOS patients who consume a KD exhibit activated adenosine monophosphate-activated protein kinase (AMPK) and silent mating type information regulation 2 homolog 1 (SIRT1), both of which are typically observed with calorie-deprived diets. KD causes weight loss and reduces fat mass, both of which reduce insulin secretion after meals, restoring insulin sensitivity and improving glucose tolerance. In PCOS, KD can reduce androgen levels and normalize the ratio of luteinizing hormone (LH) to follicle-stimulating hormone (FSH).
For many years, women with PCOS have been advised to lose 5%-10% of their body mass to restore insulin sensitivity and glucose tolerance, as these factors are essential for restoring metabolic regulation. The current study suggests that the VLCKD could potentially help treat PCOS in the long term as a result of its considerable success in achieving weight loss, improving body composition, and reversing insulin resistance. It is evident that the nutritional approach in treating PCOS is essential, whether in controlling body weight, IR, or treating associated comorbidities through different strategies.
KD and PCOs: A Cleveland Clinic Study
A small case study at the Cleveland Clinic has shown promising results of weight loss in women with PCOS with the keto diet. Four women were followed for six months on a ketogenic diet at the Cleveland Clinic’s Obesity and Weight Management program.
With PCOS, “looks” do not count and it takes more than just a BMI or pelvic ultrasound to make the right diagnosis and provide the right treatment. If you are experiencing any of the symptoms of PCOS or have been diagnosed and experiencing infertility issues, it is time to schedule an appointment.
Ketogenic Diet as Medical Prescription in Women with Polycystic Ovary Syndrome (PCOS)
The hallmark features of oligo-anovulation, hyperandrogenism, and polycystic ovaries have been recently challenged, as the sonographic criteria from the Rotterdam Consensus may easily lead to misinterpretation, especially among the postmenarcheal teenagers and in women with regular, ovulatory cycles who happen to have strings of visible antral follicles and a dominant follicle or corpus luteum. Therefore, apart from history of contraceptive hormones use or fertility treatment, the day of the menstrual cycle during assessment, together with its length and pattern should also be reviewed prior to making diagnosis.
Weight loss diets have become a fad among health enthusiasts. Recently, ketogenic diet has been making a comeback due to its potential to delay aging and as an effective fat burner. It is seen as a potential dietary intervention to help women with PCOS to lose weight and maintain weight loss, improve sex hormones level (hence fertility), optimize cholesterol level, and normalize the menstrual cycle.
Despite the suggested promising effects of ketogenic diet in women with PCOS, the evidence was relatively patchy, conducted in a heterogeneous setting in a small population and over a short time period. Therefore, our study aimed to assess the effects of ketogenic diet on reproductive hormone levels among women with PCOS: luteinizing hormone to follicle-stimulating hormone (LH/FSH) ratio, sex hormone binding globulin (SHBG), progesterone, and free and total testosterone level, following at least 45 days of intervention with ketogenic diet.
Single-arm interventional studies that reported a measure of association (with mean difference and SD, or sufficient data to calculate them) in the level of reproductive hormones of interest were considered eligible for inclusion.
Findings from the 2 authors were collated using Mendeley Desktop 1.19.8. Data extraction using a standardized form was carried out by a single author (K.K.) whose primary interest lies in clinical endocrinology. The Cochrane Risk of Bias Tool for randomized trials was used for evaluation of bias (Supplementary Material) [16].
The pooled results were reported as mean difference and presented with 95% CI with two-sided P values. Meta-analysis was conducted if at least 2 studies were available for a particular outcome. The robustness of the results was established by eliminating each study one by one from the meta-analysis and recalculating the summary estimate (the “leave-one-out” approach). If ≥5 studies were available, the possibility of publication bias was explored by visual inspection of the funnel plot of the effect size against standard error.
The initial search from ScienceDirect database using the same search strategy produced 1928 articles. The search produced a total of 161 articles from the 4 databases selected. After title and abstract screening, only 7 articles were selected for the evaluation of the full text. The overall analysis included 170 participants. Four studies were conducted in Italy [15, 17-19], 2 in China [13, 14] and 1 in the United States [20]. Assessment of dietary compliance was performed via evaluation of urine or blood ketosis in 4 studies [13, 14, 17, 20], counseling or phone reminder in 2 studies [14, 15], and food records [20].
Meta-analytic pooling under a random-effects model indicated a significant association between ketogenic diet and reduced LH/FSH ratio (d −0.851; 95% CI −1.015, −0.686; P < .001) (Fig. 2) in a population of 112 subjects.
We also found a statistically significant increment in serum SHBG following ketogenic diet intervention (d 9.086; 95% CI 3.379, 14.792; P = .002) (Fig. 4). A leave-one-out sensitivity analysis was performed by iteratively removing one study at a time to confirm that our results were not determined by a single study. There was no change in the result of the main analysis for each of the outcomes tested.
The present study is the first systematic review with meta-analysis that evaluated evidence of association between ketogenic diet and reproductive hormone levels among women with PCOS in a pool of 170 subjects. The pooled analysis of eligible clinical trials, each carried out in a limited number of subjects, showed a possible improvement in LH/FSH ratio, serum free testosterone and serum SHBG.
In this study, we found that a ketogenic diet significantly reduced the LH/FSH ratio [14, 15, 18, 19].
Apart from reducing LH/FSH ratio, our study also found that a ketogenic diet reduced the level of free testosterone in women with PCOS [14, 15, 18, 19].
Dietary modification with ketogenic diet was found to increase the level of circulating SHBG [15, 18, 19] and hence improved metabolic and ovulatory dysfunction in women with PCOS. The low-carbohydrate ketogenic diet was speculated to result in reduction in hyperinsulinemia and therefore decreased stimulation of ovarian androgen production as well as increased SHBG levels, synergistically limiting the circulating free androgens [20].
Our pooled analysis did not find any changes in serum progesterone level following intervention with ketogenic diet. However, the number of subjects available for pooled analysis were small; hence, this finding needs careful interpretation and reassessment when more studies become available.
Our secondary outcome measurement was evidence of weight changes with a ketogenic diet. All included studies noted significant weight loss following very low-carbohydrate, ketogenic diets.
In conclusion, herein we reported the possible association between ketogenic diet and improvement in reproductive hormone levels in women with PCOS via meta-analysis of the available and usable studies. The accessible literature still has several limitations necessitating careful review, reducing the applicability and transferability of these results to the general PCOS population.
Ketogenic Diet for PCOS: Fixing the Problem
For women affected by polycystic ovarian syndrome (PCOS), changing to a ketogenic diet to reduce insulin levels may improve fertility. Patients often see weight loss results-which helps reduce PCOS symptoms-but women with PCOS see improvements because the problem in PCOS is carbohydrate/insulin resistance. “The link between insulin resistance and PCOS is very well studied,” says Ula Abed Alwahab, MD, an endocrinologist at Cleveland Clinic. “If we are able to control insulin resistance, then we are able to reduce many of the PCOS symptoms and complications, including weight, diabetes, high blood pressure, heart disease, and infertility.”
Dr. Abed explains that the traditional treatment route for PCOS is essentially to treat the symptom. If a patient has irregular periods, her doctor would treat her with birth control pills just to her regular period without focusing on the consequences of that, or how much weight she might gain. If the patient has infertility, she would be given fertility treatments even though they are not always successful because of the other problems associated with PCOS. Dr. Abed’s team aims to achieve all of the goals of women with PCOS, such as weight loss, regular periods or pregnancy with higher success rates.
While diabetes medications have been used in the past to treat PCOS, most of these medications return only varying success. However, Dr. Abed notes that after her team saw improvement among her diabetes patients after they began following the ketogenic diet, they decided to explore if the same benefits with insulin resistance could work with their PCOS patients.
Dr. Abed explains that when she meets with a patient with PCOS, with a BMI more than 30 and is trying to control the symptom or wants to become pregnant, starting the patient on a ketogenic diet is the first option given. The patient comes back for a monthly shared medical appointment. Dr. Abed says, “We start the session with a dietitian piece about women’s health, diet, exercise, lifestyle; it changes every month, and our dieticians work really hard every month to create a 20-minute discussion. After those first 20 minutes, we go around the table and I talk to each patient and address their issues individually, and I see where they are at in their progress. People really enjoy the experience and they get way more benefit from doing the shared medical appointment than just talking to me one-on-one.”
Dr. Abed says the results so far have been very good. Because they are being put on a restricted diet, her patients have been losing weight. Many of her patients are also reporting regular periods again. “We are seeing that many of our patients who are interested in pregnancy are now able to achieve pregnancy,” says Dr. Abed. “Some are even able to achieve pregnancy without medications. These are patients who have struggled with pregnancy, and now we are seeing them able to achieve pregnancy and eventually a live birth. That’s what we’re aiming for with this program-to get a live birth successfully with the program.”