The Ketogenic Diet and Fertility: Benefits, Risks, and What the Research Shows

Medically Reviewed by Dr. Silvana Chedid on August 13, 2026

The ketogenic diet’s effect on fertility depends largely on why a person is having trouble conceiving. Research on women with polycystic ovary syndrome (PCOS) suggests the diet can improve ovulation, while its effect on fertility more broadly, and on outcomes during IVF, is far less settled. Understanding what the ketogenic diet actually does, and does not do, matters before making it part of a fertility plan.

At Chedid Grieco, patients researching every possible way to improve their chances before or during treatment ask us about diet often, and the ketogenic diet is one of the most common questions we get. Our assisted reproduction consultations always start with a full picture of a patient’s health, including nutrition, because a diet that helps one person can do nothing, or even work against another, depending on the underlying cause of infertility.

What Is the Ketogenic Diet?

The ketogenic diet is not new. It has been used since the 1920s, originally as a treatment for epilepsy, long before it became popular for weight loss. The approach reduces carbohydrate intake to less than 50 grams per day while increasing fat and protein intake substantially. In practice, this typically means roughly 70 to 80 percent of daily calories come from fat, about 20 percent from protein, and only around 5 percent from carbohydrates.

Restricting carbohydrates this sharply forces the body to change how it produces energy. Carbohydrates are normally the body’s primary fuel source through glucose, so when that supply drops, the body first draws on glycogen stored in the muscles and liver, then shifts to burning fat for fuel, a metabolic state called ketosis. This shift is what drives the diet’s rapid early weight loss, and it is also why the diet is difficult to sustain. A review published in the Journal of Clinical Neurology found that only 45 percent of participants were able to follow the diet as prescribed over time, with low adherence attributed to side effects, social isolation around food, and persistent cravings.

Foods Allowed on the Ketogenic Diet

The ketogenic diet menu centers on sources of fat and protein. Typical foods include chicken breast, red meat, fish, eggs, pork, unprocessed deli meats like turkey breast and ham, cottage cheese, oilseeds, olive oil, butter, lettuce, and dark green vegetables such as broccoli and spinach, along with most cheeses. Starchy vegetables, grains, most fruits, and added sugars are excluded almost entirely.

How the Ketogenic Diet May Affect Ovulation and Hormones

The strongest evidence for a fertility benefit from the ketogenic diet comes from research on PCOS, one of the most common causes of ovulatory infertility. A 2024 study of women with PCOS found that a ketogenic diet may improve ovulation and fertility rates regardless of whether patients were also using metformin or ovulation-induction medication. Related research published in Nutrition, Metabolism and Cardiovascular Diseases has similarly found that adding a ketogenic dietary intervention alongside IVF treatment improved fasting glucose, triglycerides, and waist circumference in PCOS patients, though it did not measurably change ovarian response or embryo development during the IVF cycle itself.

Taken together, this research points to the diet’s effect running mainly through weight and insulin sensitivity rather than a direct effect on egg or embryo quality. For patients with PCOS, that mechanism still matters, since improving ovulatory function is often the first step toward conceiving. For patients without PCOS or another insulin-related condition, the evidence for a fertility benefit is much thinner. A hormonal and reproductive health evaluation is the most reliable way to find out whether an insulin-related or ovulatory issue is part of the picture before adopting a restrictive diet to try to improve it.

Common Side Effects

Because the diet changes how the body produces energy so abruptly, it is common to notice side effects within the first few days, including headaches, body aches, and general malaise, sometimes called the “keto flu.” Research has also flagged several other effects worth considering before starting:

• Muscle loss
• Kidney overload
• Liver problems
• Cold sensitivity
• Mood changes
• Nutritional deficiencies
• Dehydration and electrolyte loss

These effects are one reason providers generally recommend medical supervision before starting the diet, particularly for anyone already managing a hormonal condition or actively trying to conceive.

What the Research Says About Keto and Cancer

Some patients ask about the ketogenic diet in the context of cancer, since normal cells can shift into ketosis and use fatty acids for energy while some cancer cells appear less able to do the same. However, the body still produces glucose even without dietary carbohydrate intake, and evidence suggests some cancer cells are able to survive and continue dividing under these conditions regardless. A small 2012 study published in the journal Nutrition placed 10 patients with advanced cancer on a ketogenic diet for 28 days; four saw the disease continue to progress, five stabilized, and one had a partial remission. The sample size is far too small to draw conclusions, and no major medical body currently recommends the ketogenic diet as a cancer treatment. Larger, controlled studies would be needed before any conclusion could be drawn.

Weighing the Benefits and Risks Before Trying Keto for Fertility

The ketogenic diet’s most consistent, well-documented benefit is rapid early weight loss, which happens because the body burns through its glycogen reserves once carbohydrates are restricted, followed by a shift into fat burning. For patients whose infertility is connected to excess weight or insulin resistance, this initial progress can be motivating and may support a longer-term, more sustainable approach to eating afterward.

The tradeoffs are real, though, and worth naming directly.

Fatigue and Difficulty Concentrating

Without carbohydrates, the brain has less glucose available to draw on, which commonly shows up as fatigue and trouble concentrating, especially in the first few weeks.

Mood Changes

Carbohydrates help transport tryptophan to the brain, where it supports serotonin production. Reducing carbohydrate intake sharply can disrupt that pathway and contribute to low mood for some people.

Hypoglycemia

Drastically cutting carbohydrates can cause blood sugar to drop low enough to trigger dizziness or fainting in some patients, particularly early in the diet.

Muscle Loss and Cholesterol Changes

When carbohydrate stores run low, the body can turn to amino acids in muscle tissue for fuel, working against the goal of healthy, sustainable weight loss. Because the diet also encourages higher saturated fat intake, some patients see a rise in LDL cholesterol, which carries its own cardiovascular considerations independent of fertility.

Talk to Your Care Team Before Starting Any Restrictive Diet

Diet is one factor among many in a fertility plan, and it rarely works in isolation. Before starting the ketogenic diet or any other significantly restrictive eating pattern while trying to conceive or preparing for in vitro fertilization, it is worth reviewing the plan with your physician so it can be weighed against your specific diagnosis, medications, and treatment timeline. What helps one patient with PCOS improve ovulation may do very little for a patient whose infertility has an entirely different cause.

Frequently Asked Questions About the Ketogenic Diet and Fertility

Have Questions About Fertility and Nutrition? Contact Chedid Grieco

Every fertility plan should be built around your specific diagnosis, not a general diet trend. Our team reviews nutrition, hormonal health, and treatment history together during every consultation, so any dietary change you are considering, keto or otherwise, gets weighed against what is actually driving your fertility challenges.

If you have questions about how diet fits into your fertility plan or want to explore assisted reproduction options, reach out through our contact form and our team will be in touch.