PCOS and Weight Gain

By Britni Vincent, RD, LD
April 22, 2024

PCOS.jpgYou may not have heard of PCOS (polycystic ovarian syndrome), but it is one of the most common endocrine disorders in women and is the number one cause of infertility for women. You may even know somebody who has PCOS since it affects 5 – 10% of women in the United States and at least 50% of women go undiagnosed (1,2).

In this article, I'll cover what polycystic ovary syndrome is, how PCOS affects the whole body, why many women with PCOS experience weight gain, and  how lifestyle and dietary changes can address PCOS related weight gain and other PCOS symptoms that may be negatively impacting your quality of life.  

What Is Polycystic Ovary Syndrome (PCOS)?

Polycystic ovary syndrome, PCOS for short, is a syndrome – meaning it can manifest with different symptoms and look different for each woman. If you’ve done research on this you’ll notice it’s also called polycystic ovarian syndrome. Both are correct. There can be many different combinations of symptoms and different contributing factors to a woman’s PCOS.

In fact there are different types of PCOS, also known as phenotypes of PCOS. Diagnosis occurs during menstruating years, but the syndrome is generally present throughout a woman’s lifespan from puberty through post-menopause.

Symptoms can include: 

  • weight gain
  • difficulty losing weight
  • acne
  • infertility
  • hair loss
  • depression
  • irregular menstrual cycles
  • excessive hair growth of facial hair or body hair (hirsutism)
  • ovarian cysts

It is a complex condition that affects the body systemically, meaning it doesn’t just affect one part of the body or one organ like the ovaries, but rather the whole body or multiple systems. Because of that, for most women with PCOS, it’s not just an endocrine disorder it’s also a metabolic disorder, which is one reason why women can experience challenges when trying to lose weight.

Women with PCOS do have increased risk factors for type 2 diabetes, heart disease and an autoimmune thyroid gland condition called Hashimoto’s.


Getting a PCOS Diagnosis

Diagnosis of PCOS can take a long time and often women don’t get diagnosed until they are struggling with infertility. There is an international consensus to diagnose PCOS which is referred to as the Rotterdam criteria. Using the Rotterdam criteria, a woman needs to meet at least two of the three following criteria:

  • Irregular menstrual cycle/anovulation
  • Hyper androgenism – this can be determined based on symptoms such as hirsutism (excess facial hair and body hair), acne, oily skin, hair loss and/or lab tests showing elevated androgens (DHEA and testosterone)
  • Polycystic ovaries seen on an ultrasound

The assumption for many practitioners is that if you have PCOS you’re going to be overweight. And yes, excess weight gain is a common symptom of PCOS, but not all women with PCOS are overweight, which is just another reason why so many women at a healthy weight fall through the cracks and don’t get diagnosed.

Potential Causes of PCOS

The simple answer is that experts don’t know the cause of polycystic ovarian syndrome yet. What makes PCOS hard to categorize is that the syndrome includes different types of PCOS and the development of PCOS is multifactorial, but often involves insulin resistance (3). There’s ongoing research to determine what really is the cause of PCOS and experts say there isn’t one cause for everyone across the board. It’s also a little bit of what come first, like the chicken or the egg.

1. Hyperandrogenism

Currently, research is pointing to the idea that some women may develop hyperandrogenism (excess androgen production, which are hormones like testosterone and DHEA) at puberty. Androgens are thought of as male hormones, but they do play important roles in the female body. However when women produce too much of them than it can become problematic.

Hyperandrogenism can cause weight gain, specifically more visceral fat – or belly fat. The excess visceral fat can lead to or exacerbate insulin resistance and the elevated insulin can exacerbate the excess androgens.

This can become a vicious cycle that’s hard to break. Another pathogenesis is that insulin resistance can cause excess androgens and again the excess androgens can contribute to weight gain , which will in turn exacerbate the insulin resistance. There isn’t currently a consensus on the exact cause of insulin resistance in PCOS.

2. Unbalanced Gut Microbiome

Recent studies have looked at the role of the gut microbiome as a cause or effect of weight gain, insulin resistance, and inflammation in PCOS. Gut dysbiosis caused by a diet of processed food could create damage to the gut, which results in the activation of the immune system, insulin resistance, and hyperandrogenism (excess androgens) in women with PCOS. All of this can contribute to PCOS related weight gain.

3. Increased Inflammation

Low grade chronic inflammation is usually seen in women with PCOS. This can sometimes be seen with elevated white blood cell count and high levels of C-reactive protein (CRP). Insulin resistance, hyperandrogenism, fat cells and gut dysbiosis can all contribute to inflammation. Low grade chronic inflammation can also be caused by stress, a diet high in sugar or processed foods, lack of sleep, chronic illness, etc.

4. Genetics and PCOS

The role of genes and PCOS hasn’t been determined. Some women may be predisposed, but even if a woman is predisposed that doesn’t mean it’s her destiny. If someone is genetically predisposed to PCOS it is often the interplay of genes, environmental influences, and lifestyle factors that contribute to the development of PCOS.

Weight Gain PCOS Connection

Weight gain is a common symptom of PCOS, but being overweight does not necessarily cause PCOS. As I have already described, there are multiple factors that contribute to weight gain in women with PCOS, but insulin resistance is the MAIN cause of weight gain in PCOS.

65 to 95% of women with PCOS are estimated to have insulin resistance (4). Insulin resistance is a major contributor to weight gain and a big reason why women with PCOS have difficulty losing weight.

As you can see, there could be multiple reasons why someone would develop PCOS and it could be multiple factors happening at the same time. It's easy to get overwhelmed and feel a little helpless when so many variables could be at play and when changing your body composition feels impossible. Before you get discouraged, there are some real holistic steps you can take to improve your metabolic rate and lose weight, if that's your health goal.

Because insulin resistance seems to go hand in hand with PCOS in many cases, let’s look at some reasons why that might be and what you can do about it to prevent weight gain and achieve sustainable weight loss.

PCOS And Insulin Resistance

There is still no consensus on the exact mechanism that leads to insulin resistance in PCOS, regardless of body mass index (BMI) (3). As other tissues in your body become more insulin resistant, your pituitary gland and ovaries retain their insulin sensitivity. This is why an excess production of insulin can cause a negative cascade effect on your sex hormones resulting in abnormal hormone levels, anovulation (lack of ovulation), and irregular menstrual cycles

At Nutritional Weight & Wellness we often talk about insulin resistance, but you may not know exactly what that is. To explain, let's back up and talk about what SHOULD happen with a healthy metabolism.

How Does A Healthy Metabolism Work?

First, when you eat carbohydrates your blood sugar spikes and your pancreas naturally puts out insulin to naturally regulate your blood glucose levels. Then insulin grabs onto the glucose in the bloodstream and carries it into the cells. Insulin acts like a key to unlock the door of the insulin receptors and carry glucose into the cell to convert it to energy. Insulin is our primary fat storage hormone and is also a master hormone, which means it affects many different areas of the body.

What Is Insulin Resistance?

Becoming resistant to the hormone insulin generally develops over time from eating excess carbohydrates and sugar. The body has to produce extra insulin for the excess sugary foods consumed. Over time the insulin receptors don’t work as efficiently – the key (insulin) to unlock the receptor in the cell doesn’t work as well, creating an impaired glucose tolerance in the cells.

Consequently, there is less glucose getting carried into your cells and more glucose in your blood stream. Your body then needs to make more insulin to compensate.

Since you aren't getting as much glucose into the cells, your body wants more sugar. Your body thinks that if you eat more sugar, you'll be able to turn more glucose into energy. The more insulin your body makes, the more fat is stored and it easily turns into a vicious cycle of eating more sugar and storing more body weight.

PCOS Insulin Resistance

In the case of PCOS, excess androgens also increases insulin resistance as I mentioned above. There may be other reasons that have yet to be determined why women with PCOS are more likely to be insulin resistant. It is possible that women with PCOS may have a defect in their insulin-signaling pathways, which means they more easily become insulin resistant. This will then affect sex hormones and can lead to the other symptoms of PCOS listed above.

Women with PCOS have about a seven times greater risk for developing diabetes and are also at a greater risk for cardiovascular disease. Dr. Gersh, a leading expert on PCOS and an integrative gynecologist, supports the idea that women with PCOS are very sensitive to sugar and explains that when a woman with PCOS consumes carbohydrates it “triggers an explosion of inflammation”.

Reversing Insulin Resistance

The good news is— there is hope! For a lot of women if you focus on the insulin resistance, you will reduce a lot of drivers of your PCOS symptoms. If insulin is reduced there is a positive cascade effect systemically and a lot of times ovarian function will improve. The ovaries start to produce more progesterone, making your menstrual cycle more regular, and your androgens reduce which can reduce hair loss and excess facial hair and body hair. In women with polycystic ovarian syndrome, I focus on dietary changes first to help fix hormone imbalance.

So again, if you are feeling overwhelmed by all of the factors and symptoms that come along with polycystic ovary syndrome, I recommend focusing on improving insulin sensitivity. This can be accomplished by diet and lifestyle changes.

Treating PCOS And Reducing PCOS Related Weight Gain

The medical community agrees that healthy diet and lifestyle changes should be the first line of treatment for PCOS and will address weight gain related to PCOS.

Ultimately, what works best for one person may not be the best for the next person, but we do know that looking at the big picture, eating more real food and less processed, sugary foods is going to create better results.

Here are some specific areas of diet modifications and habits of healthy living to focus on:

1. Reduce Carbohydrates And High Sugar Foods

 Ideally, you should eliminate or extremely limit processed carbohydrates (pasta, bread, crackers, cereal, baked goods, etc.). Replace those processed carbs with lots of vegetables. For example, think a small amount of sweet potato and other vegetables with your eggs instead of toast for your breakfast.

2. Focus On Fiber

Aim for at least 25 grams of fiber each day. Fiber intake provides many benefits such as:

  • Aiding in weight loss, specifically studies have shown it can help reduce visceral fat (fat storage around organs) that women with PCOS are more likely to have
  • Increases satiety, making you fuller longer
  • Improves the gut microbiome by feeding the good bacteria
  • Blood sugar is better balanced when fiber is consumed with each meal, which will in turn reduce insulin resistance

Ground flax seeds, chia seeds, raspberries, avocado, kale, and green peas are examples of some high fiber foods. By increasing vegetable intake, your fiber intake will consequently increase and it will also help you with step 1 of reducing processed carbs! It's a win-win.

Heart Healthy Fats Omega 3s.jpg3. Add In Healthy Fat

Next, remember that fat is your friend! Fat has no effect on blood sugar so it helps to keep your blood sugar stable and decreases the amount of insulin your body produces. That means your body can start burning fat instead of storing it.

You should be eating a generous amount of fat every time you eat (1 Tbsp of butter, olive oil or coconut oil, ¼ c. nuts, ½ avocado or 14 green olives).

Avoid refined oils such as canola oil, soybean oil, vegetable oil, grapeseed oil, corn oil, and cottonseed oil. These oils are highly processed and inflammatory and can contribute to hormonal imbalances.

4. Prioritize Protein

Adequate protein intake is critical for weight loss. Protein, in addition to strength training, is the key to building muscle. When people have a weight loss goal they also want to build muscle too. Not only does protein build muscle, protein keeps you fuller longer, stabilizes blood sugar and therefore reduces cravings.

There is some variability from person to person but most women should aim for 4-5 ounces at meals (28-35 grams). Protein sources include: meat (ideally organic, grass-fed, free range, or pasture-raised), eggs (ideally organic pasture-raised), fish and seafood (ideally wild-caught) and dairy if tolerated (many women with PCOS see better results without dairy).

5. Try To Incorporate Movement Each Day

Exercise provides many benefits for women with PCOS. Exercise has the ability to:

  • Improve insulin sensitivity (this means that glucose is getting carried into the cells more efficiently)
  • Boosts mood and energy
  • Supports better sleep
  • Improve ovarian function
  • Increase lean body mass, which increases metabolism

I often get asked about what type of physical activity is best. Although this isn’t my area of expertise, I can provide a few helpful tips. If you aren’t exercising right now, any sort of movement is going to benefit you, even if it’s just walking for 15 minutes per day. Once you get in the routine of physical activity, you can increase the time and/or change the type of exercise.

Strength training whether that be using weights, resistance bands or body weight exercises will all help to build muscle more than cardio. Generally, high intensity exercises are not recommended for women with PCOS. High intensity exercise can create more stress on the body and in some cases contribute to hormonal imbalances.

6. Aim For 7 ½ - 9 Hours Of Sleep Each Night

Getting adequate sleep is critical. Lack of sleep can contribute to weight gain, insulin resistance and cravings. Optimal is getting 7 ½ to 9 hours of sleep each night. This might mean you need to go to bed earlier. What has worked for some of my clients is going to bed 15 minutes earlier until they reach their optimal bedtime to get adequate sleep.

Prioritize sleep hygiene: avoid electronics before bed (ideally an hour before bed), dim any lights at night, ensure your sleeping environment is cool, refrain from doing strenuous physical activity too close to your bedtime and instead try some gentle stretching and deep breathing. If you have difficulty falling or staying asleep we have solutions for you.

7. Be Mindful Of Endocrine Disruptors

There are environmental chemicals that disrupt our hormone production, known as endocrine disruptors. Currently, it’s unknown how much these endocrine disruptors contribute to the development of PCOS. At the very least, they have the potential to exacerbate PCOS symptoms, including weight gain.

The endocrine disruptors are found everywhere like the mattress you sleep on for 1/3 of your day, all the lotions and personal care products you put on your skin and hair, plastic water bottles, plastic food containers, and the list goes on and on. Here are just a few steps you can take to reduce your exposure to endocrine disruptors:

  • Check out the Skin Deep database to see how toxic your household and personal care products are
  • Ditch your plastic food containers and water bottles and switch to glass or stainless steel
  • Drink filtered water

Hormone Disruptors Social Media Graphics.jpg

Hope For PCOS Recovery

I have PCOS and can proudly say that through diet changes and individualized supplementation I have been able to start ovulating on my own, which allowed me to have three beautiful children. I know that I have to be extra mindful of my diet and lifestyle choices to keep my symptoms at bay, but healthy living is possible.

PCOS affects the whole body and is a disorder that requires an individualized treatment plan. If you resonated with this article you don't need to have a polycystic ovary syndrome diagnosis to start making dietary and lifestyle changes to improve symptoms! You can start now by decreasing processed carbohydrates, focusing on fiber, healthy fat, and protein.

If you know anybody struggling with infertility, weight management, or any of the symptoms discussed above, please share this article. It may provide some answers they've been looking for.

If you have PCOS, I highly recommend scheduling an appointment with a nutritionist. I believe that women with PCOS need more support and somebody to support them through their journey!

For more information on hormone health and weight loss, check out these resources:

READ: Why Women Need Protein For Weight Loss - why you need protein, signs your not getting enough, how much protein you need for weight loss and body composition changes, and how to make it happen

LISTEN: Insulin Resistant or Not - Ask A Nutritionist - dietitian Leah covers what insulin resistance is, signs you might have it, and lab tests you can look into for more data

INSPIRE: McKayla's Story of Ending Endometriosis Pain with real food


1.     Polycystic ovary syndrome. Polycystic ovary syndrome | Office on Women’s Health. (n.d.). https://www.womenshealth.gov/a-z-topics/polycystic-ovary-syndrome

2.     PCOS awareness association. PCOS Awareness Association. (n.d.). https://www.pcosaa.org/

3.       Armanini, D., Boscaro, M., Bordin, L., & Sabbadin, C. (2022). Controversies in the pathogenesis, diagnosis and treatment of PCOS: Focus on insulin resistance, inflammation, and hyperandrogenism. International Journal of Molecular Sciences, 23(8), 4110. https://doi.org/10.3390/ijms23084110

4.     Zhao, H., Zhang, J., Cheng, X., Nie, X., & He, B. (2023). Insulin resistance in polycystic ovary syndrome across various tissues: An updated review of pathogenesis, evaluation, and treatment. Journal of Ovarian Research, 16(1). https://doi.org/10.1186/s13048-022-01091-0

























About the author

Britni is a licensed dietitian at Nutritional Weight & Wellness. Britni once struggled with insomnia, acne and regular migraines that would force her to retreat to a dark room for relief. She tried several different approaches to feel better before she realized her diet was the culprit and changed her eating to a more balanced approach. As a result, her insomnia and acne are gone, and she rarely has migraines. Britni is a registered and licensed dietitian through the Minnesota Board of Nutrition and Dietetics. She received her B.S. in dietetics from the University of St. Thomas and completed her dietetic internship at the University of Iowa. She has experience in nutrition counseling, leading seminars and motivating clients of all ages to make changes.

View all posts by Britni Vincent, RD, LD


Nicole Roman
Good morning,

I am twenty year old woman and I have not had regular periods for a long time. I saw and OB yesterday and she is encouraging me to seek out dietary help with getting my weight and health on track. I am a latina with a long family history of diabetes and heart disease. I have gone to your classes before with my Mom and she suggested we try this approach to get me on track. I have gained a lot of weight in the last 2 years.
December 2, 2020 at 10:30 am


Hi Nicole,

We would definitely recommend setting up a one-on-one appointment with one of our nutritionists. 

Leave a comment

Your email address will not be published. Required fields are marked *

Back To Top