The PCOS Diet Ultimate Guide – Best and Worst Foods

Article written and reviewed by Kylie Buckner, RN, MSN
Published February 27, 2020
PCOS Diet Ultimate Guide

Polycystic ovarian syndrome (PCOS) is one of the most common endocrine disorders in women and, yet, there’s still a lot to learn about the condition, including whether or not a PCOS diet can help address related symptoms.

After all, while a growing body of research has led to an increased understanding of the genetic, metabolic, endocrine, and environmental causes of PCOS, women with the disorder are seeking to learn more about effective non-pharmaceutical dietary treatment options.

In this article, we’ll help you understand the biology of PCOS (and why it’s a major cause of infertility worldwide), what pharmaceutical treatment options are available, and an incredibly effective PCOS diet aimed at reversing the underlying cause of many PCOS symptoms.

In my experience as a nurse working in both high-risk OBGYN and fertility clinics, I have seen the direct impact of a PCOS diagnosis. I have also helped many women living with PCOS understand how specific lifestyle changes can improve their symptoms and significantly increase the chances of pregnancy.

Many women living with PCOS are frustrated by the lack of effectiveness of the current medical model to improve both short-term and long-term health, resulting in an increasing collection of symptoms over time.

What Is the Biology of PCOS?

PCOS is an endocrine disorder that affects approximately five to 10 percent of all women of reproductive age. It is considered a multifactorial disorder with genetic, metabolic, endocrine, and environmental causes. 

The causes of PCOS are yet to be fully explained, but scientific evidence suggests that PCOS occurs in women with a genetic predisposition, and often begins as the fetus is developing in utero.

PCOS is caused by an imbalance between male reproductive hormones (androgens) and female reproductive hormones (estrogens). Women with PCOS overproduce androgens and under produce estrogens, resulting in the development of painful ovarian cysts that greatly affect reproductive biology.


PCOS is an endocrine disorder that is affected by genetic, metabolic, endocrine, and environmental causes. As a result of its complicated nature, it’s important for each woman dealing with PCOS to discover a multi-step plan that works best to address her specific symptoms.

What Are the Symptoms of PCOS?

Living with PCOS can be very challenging and present a collection of unwanted symptoms including:

  • Ovarian cysts
  • Acne
  • Facial hair growth
  • Weight gain
  • Depression
  • Painful and irregular menstrual cycles
  • Infertility

The majority of women diagnosed with PCOS develop numerous ovarian cysts, fluid filled sacs that can become very painful when they rupture, causing severe and intermittent lower abdominal pain.

In the same way that metabolic conditions like cancer, diabetes, and heart disease often have a genetic basis from birth but remain dormant until the right collection of environmental triggers present later in life, PCOS is present at a young age but often first presents symptoms at puberty and continues into a woman’s reproductive years. 

In addition to the development of ovarian cysts, PCOS can dramatically increase a woman’s risk for many metabolic conditions, including: 

  • Cardiovascular disease
  • Hypertension
  • Pre-eclampsia 
  • Insulin resistance and diabetes (including prediabetes, type 2 diabetes, and gestational diabetes)
  • Miscarriage 
  • Infertility

In fact, according to a 2018 review, the prevalence of metabolic syndrome is as high as 33 percent in women with PCOS. 


PCOS is a challenging disorder that not only comes with a host of unwanted symptoms, but may increase a woman's risk for other metabolic conditions, including cardiovascular disease, miscarriage, and infertility.

The Connection Between PCOS and Insulin Resistance

One of the most common symptoms of PCOS is insulin resistance, the precursor condition to both prediabetes and type 2 diabetes. As a result, women living with PCOS are at an advanced risk for the development of prediabetes, type 2 diabetes, and gestational diabetes.

Insulin resistance is caused by the accumulation of excess saturated fat inside tissues that are not designed to store large quantities of fat, namely muscle and liver.

(NOTE: For an in-depth overview of the causes of insulin resistance, read Mastering Diabetes.) 

But you might be wondering: Why does PCOS cause insulin resistance? Or, at the very least, how are the two linked? The short answer is that it’s not uncommon for women with PCOS to have insulin resistance, especially if they are already overweight or juggling a family history of diabetes.

The result? Accumulation of excess saturated fat in liver and muscle inhibits insulin signaling in both tissues, resulting in the following:

  • Reduced uptake of glucose from the blood
  • Elevated fasting and post-meal blood glucose values (hyperglycemia)
  • Excess insulin production (hyperinsulinemia)
  • Elevated A1c

Women living with PCOS and insulin-dependent diabetes can directly measure increasing insulin resistance simply by tracking their 24-hour carbohydrate-to-insulin ratio or their mealtime carbohydrate-to-insulin ratio using the Decision Tree.

Women living with non-insulin-dependent diabetes can indirectly track the symptoms of increasing insulin resistance using the Insulin Resistance Checklist, or directly measure their level of insulin resistance using an oral glucose tolerance test (OGTT) at the doctor’s office or laboratory. 

In both cases, increasing insulin requirements over time, whether exogenous (injected) or endogenous (manufactured by your own pancreas) are a strong indicator that insulin resistance is increasing over time, increasing your risk for the development of many chronic diseases.

Indirect signs of insulin resistance include (but are not limited to):

  • Weight gain
  • Increasing blood pressure
  • Increasing LDL cholesterol
  • Increasing triglycerides
  • Increasing A1c
  • Increasing fasting blood glucose
  • Feeling low energy
  • Excessive thirst


If you are dealing with PCOS and insulin resistance, then it’s important to take specific measures to address both conditions. Take time to track your 24-hour carbohydrate-to-insulin ratio or your mealtime carbohydrate-to-insulin ratio by using the Decision Tree.

The Effects of Excess Testosterone In Women

Hyperinsulinemia in particular presents a serious problem for women living with PCOS because excess insulin stimulates testosterone production, which further exacerbates many of the symptoms of PCOS, causing a feedback loop that can dramatically reduce long-term health.

There are numerous symptoms of excess testosterone production in women, including (but not limited to):

  • Painful ovarian cysts
  • Weight gain
  • Acne and oily skin
  • Hair thinning and baldness 
  • Facial and body hair growth
  • Irregular and unpredictable menstrual cycles

Excess testosterone production can also lead to infertility and obesity. In fact, a recent study published in The World Journal of Men’s Health showed testosterone can serve as a means for contraception and “should not be used in men who desire fertility.” 

The same can be said for women who produce too much testosterone as a result of PCOS and find they are struggling with fertility.


When PCOS leads to too much testosterone production, it may have a harmful impact on a woman’s overall health, including her fertility.

Common Pharmaceutical Medications to Treat PCOS

Pharmaceutical medications are often used to manage the symptoms of PCOS, but often do little to address the root causes of increasing chronic disease risk. Some pharmaceutical medications recommended to treat PCOS may even trigger other conditions. 

Ahead, you’ll discover the most commonly prescribed medications for PCOS — which are meant to be taken in addition to recommended lifestyle changes — and the pros and cons that cons along with each one. 

Hormonal Birth Control

Hormonal birth control contains synthetic hormones that have been linked to decreased acne, reduced facial hair growth, and fewer irregular menstrual cycles, three PCOS-related symptoms you wouldn’t mind seeing less of, right? 

In fact, according to a 2017 study published in the Open Access Journal of Contraception, a combined birth control pill — which pairs together estrogen and progesterone (or progestin) to reduce testosterone levels — can also help create lighter periods and reduce cramping.

But hormonal birth control also comes with its own set of not-so-great side effects, including:

  • Weight gain or loss
  • Nausea
  • Breast tenderness
  • Mood swings
  • Spotting between periods
  • Breast tenderness
  • Decreased libido
  • Increased risk of depression

Hormonal birth control is not recommended for women trying to conceive, as it significantly reduces the chances of becoming pregnant. As a result, women trying to become pregnant may experience an increase in many of the PCOS-related symptoms listed above.


Metformin is a widely prescribed oral glucose-lowering medication commonly used to increase insulin sensitivity in people living with prediabetes, type 2 diabetes, and gestational diabetes, and is also commonly prescribed for women living with PCOS. 

Metformin elicits effects on multiple tissues, including:

  • Reduced absorption of glucose in your intestine
  • Slowed release of glucose from your liver
  • Increased uptake of glucose in your muscle

Metformin does not directly reverse insulin resistance – it simply helps to control the symptoms of insulin resistance – namely elevated blood glucose, excess insulin, and elevated A1c. 

As a result, many women who use metformin to treat prediabetes, type 2 diabetes, gestational diabetes, or PCOS find that their dosage increases over time, or that they are prescribed additional glucose lowering medications to control their A1c. 

Metformin’s side effects include:

  • Gastrointestinal discomfort
  • Nausea
  • Vomiting
  • Abdominal pain
  • Bloating
  • Diarrhea
  • Cramping
  • Vitamin B12 deficiency
  • Lactic acidosis

Interestingly, metformin has not been approved by the FDA to treat PCOS, however many medical professionals do prescribe it as a method for treating the condition, according to the PCOS Awareness Association.


A third commonly prescribed medication for women with PCOS is spirinolactone (Aldactone), which functions to reduce testosterone production.

Spirinolactone has no effect on other common symptoms of PCOS including irregular menstrual cycles, weight gain, and ovarian cyst development. 

Spirinolactone is a diuretic and often produces the following side effects:

  • Kidney damage
  • Electrolyte imbalance
  • Headaches
  • Diarrhea
  • Cramps
  • Stomach pain
  • Drowsiness
  • Fatigue
  • Skin rashes
  • Nausea
  • Vomiting


To manage the symptoms of PCOS, doctors often prescribe hormonal birth control, metformin, or Spirinolactone, which may improve PCOS symptoms. However, it is important to note that while these medications may help alleviate PCOS symptoms, they do not address the root cause of PCOS, nor do they take into account the increased risk of chronic disease that may occur. Talk to your healthcare provider about how to make these medications work for you, while also addressing lifestyle changes, like adhering to a PCOS diet.

How Does Nutrition Affect PCOS?

PCOS is not a reversible condition, however its symptoms are manageable and can often be significantly reduced or eliminated using simple lifestyle changes.

Neither hormonal birth control, metformin, nor Spirinolactone target insulin resistance, which itself is a symptom of PCOS and a condition that strongly affects many of the other symptoms listed above. 

In addition, reversing insulin resistance with a plant-based diet can dramatically reduce the risk for the development of many chronic diseases that are related to insulin resistance, including:

  • Cardiovascular disease
  • Hypertension
  • Prediabetes
  • Type 2 diabetes
  • Gestational diabetes

The evidence-based research shows that the most effective tool in reversing insulin resistance is a low-fat, plant-based, whole-food diet. Simply reducing the severity of insulin resistance can lead to a dramatic reduction in the severity of many of the symptoms listed above.

Most physicians do not recommend a low-fat, plant-based, whole-food diet to treat PCOS, and many recommend a Paleo diet or ketogenic diet to limit carbohydrate intake and therefore increase insulin sensitivity.

The problem is that a growing body of scientific research is now demonstrating the effectiveness of a low-fat, plant-based, whole-food diet in improving insulin sensitivity and beta cell function in human subjects.

Although many medical professionals agree that lifestyle change is incredibly important in developing a long-term, sustainable approach to reduced chronic disease risk, often patients lack an understanding of what changes to make, how to make those changes, and how to stick with those changes over time.

Simply being told to “lose weight,” “eat a healthy diet,” or “exercise more” are subjective recommendations that leave many people feeling confused. 

While the scientific data in support of a low-fat, plant-based, whole-food diet to treat PCOS is lacking, we have found that many women living with PCOS experience a dramatic reduction in the symptoms of PCOS and are able to lose weight, lower their blood glucose, and reduce menstrual irregularity within only a few months. 

In addition, navigating this process with the support of a community and team of coaches has proven to be incredibly helpful for many women living with PCOS.


Talk to your doctor about the benefits of a low-fat, plant-based, whole-food diet to treat PCOS. If you require further support for how to make these changes, seek the support of a community who can help you better understand how your PCOS symptoms may be reduced by adhering to nutritional changes.

What Is the Optimal PCOS Diet?

By eating a wide variety of the whole plant foods listed below, you can easily increase the nutrient density of your diet and reduce the severity of PCOS symptoms. 

Our suggestions for increasing your intake of “green light foods” include:

Eat 3-5 servings of fruits for breakfast and lunch

Adding high-fiber fruits for breakfast and lunch will help decrease your saturated fat intake and reduce your fasting and post-prandial blood glucose. Fruits are an excellent source of whole carbohydrate energy, which fuel your brain, muscles, and liver and add vitamins, minerals, antioxidants, and phytochemicals to your diet.

Eat 1-2 servings of whole grains per day

Whole grains are another excellent source of whole carbohydrate energy and can help you feel full between meals. Eat 1-2 servings of whole grains including quinoa, brown rice, steel cut oats, barley, buckwheat, farro per day.

Eat 1-2 servings of legumes per day

Legumes are considered one of the most nutrient-dense foods on the planet, and are an excellent addition to a nutrient-dense diet to stay fueled throughout the day. Eat 1-2 servings of any variety of beans, lentils, peas, or chickpeas per day. 

Eat 3-5 servings of non-starchy vegetables per day

Non-starchy vegetables are some of the most nutrient dense foods on the planet, and include vegetables like tomatoes, onions, cucumbers, broccoli, cauliflower, bell peppers, asparagus etc. Eat 3-5 servings of non-starchy vegetables per day.

Eat 2-4 cups of leafy green vegetables per day

Greens (romaine lettuce, arugula, spinach, kale, collard greens, beet greens, Swiss chard, etc.) are an amazing source of vitamins, minerals, and fiber. They help to minimize blood glucose fluctuations and limit the speed at which glucose enters your blood. Include 2-4 cups of green leafy vegetables per day, especially when eating carbohydrate-rich food.

Eat 1-3 servings of herbs and spices per day

Antioxidant-rich and full of anti-inflammatory properties, fresh herbs and spices will help your food taste incredible, reduce inflammation, and add powerful phytochemicals to your diet. Eat 1-3 servings of herbs and spices per day.

What Foods Should You Avoid Living with PCOS?

Ample scientific evidence demonstrates that eating a diet high in animal foods and especially high in saturated fat is associated with increased chronic disease risk.

In addition, diets high in refined carbohydrates are associated with an increasing risk of insulin resistance.

Therefore, we recommend reducing or eliminating your intake of the following foods:

  • Processed carbohydrates (cereal, cookies, crackers, chips, pastries etc.)
  • Dairy products (milk, cheese, yogurt, ice cream, etc.)
  • Red and white meat (beef, lamb, pork, chicken etc.)
  • Fish (including shellfish)
  • Refined oils of any kind (olive oil, coconut oil, canola oil etc.)
  • Refined sweeteners of any kind (refined fructose, HFCS, etc.)
  • Eggs
  • Alcohol

In a 2017 review published in The Permanente Journal, researchers noted that a plant-based diet (versus an animal-based diet that includes processed food and refined oils) may be “especially beneficial for those with obesity, Type 2 diabetes, high blood pressure, lipid disorders, or cardiovascular disease.” 

And the list of pro plant-based diet studies goes on: In a 2019 report, researchers found a diet that is higher in plant foods and lower in animal foods is associated with a lower risk of cardiovascular disease, cardiovascular disease mortality, and all‐cause mortality.

Moral of the story? A plant-based diet might do more for you than improve symptoms of PCOS.


Being diagnosed with PCOS can be confusing, frustrating, and painful, but it doesn’t have to be. While some healthcare providers have not yet adopted a PCOS diet that can be incorporated with pharmaceutical treatments for the disorder, not all providers are familiar with a diet that can also reverse insulin resistance. 

Talk to your doctor about lifestyle changes that can be made to alleviate symptoms of PCOS, and consider seeking out a PCOS community that can help provide you with support. At Mastering Diabetes, we can provide you with the support and guidance you are looking for.

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About the author 

Kylie Buckner, RN, MSN

Kylie Buckner, RN, MSN has over 18 years of nursing experience, and is the Director of Lifestyle Change at Mastering Diabetes. She has a master's degree in nursing education and loves using her background to support people reversing insulin resistance through a low-fat, plant-based, whole-food lifestyle.

Kylie has been following a plant-based diet for over 8 years and is a certified yoga instructor. She uses all of her experience to teach about the connection between lifestyle choices and health. She has an in-depth understanding of the challenges of adopting a plant-based lifestyle and is committed to empowering people to make simple lifestyle changes. She lives in Costa Rica with her husband, Dr. Cyrus Khambatta and their two adorable cats, Mew and Blu.