Benefits of a Low-Carb Diet for Women with PCOS


Hello Cyster!

This is part 2 of our series on “PCOS and Weight Loss”. According to research, about 40 to 80% of women with the syndrome are overweight. Weight loss with PCOS has shown to greatly improve those 3 symptoms that are part of the Rotterdam Criteria, which are used to diagnose PCOS. These include the feature of polycystic ovaries, high levels of male hormones, such as testosterone and DHEA, which can cause missing periods, acne, hair loss and hirsutism, and, lastly, weight loss can help restore fertility by bringing back ovulation.

If you aren’t obese, but still want to manage your PCOS, the same approach might work for you, since it focusses on one key principle, which is keeping the hormone insulin low. Insulin is a hormone produced in the pancreas and plays a vital role in fat and glucose metabolism and is an initiator of inflammatory processes inside the body. In this post, I want to explore these roles in more detail. Let’s start off by having a closer look at insulin’s role in glucose metabolism and what happens when cells become resistant to insulin, which is the case in about 75% of women diagnosed with PCOS and one of the main driving factors of the condition.


When Cells Become Resistant to Insulin in Women with PCOS

The hormone insulin is produced in the cells of the pancreas, which is a hormonal gland located behind our stomachs. It’s secreted whenever we eat carbohydrates. During the digestive process, carbs are broken down into small sugar molecules, which enter the blood stream mainly as glucose. In order for the cells to receive these sugar molecules, which is our body’s main energy source, the hormone insulin is needed to open the door of the cells to receive the glucose from the blood stream. The more sugar enters our blood stream, the more insulin is being secreted. Sugar is burned as energy inside the cell as needed and the excess glucose is stored inside the liver as glycogen. Once these storages are full, the liver converts the excess sugar into fat, which is then exported to and stored inside the fat cells.

Insulin resistance is a blood sugar imbalance very common in women with PCOS. It’s a disease that is characterized by chronic high blood sugar and insulin levels. It mainly develops due to a diet high in carbohydrates and sugar, but a sedative lifestyle, stress and toxins may also play a role. In people with insulin resistance, the hormone insulin becomes less effective in opening the doors of the cells to receive the glucose from the blood stream and more and more insulin is needed to accomplish the job. Insulin production in the pancreas goes into overdrive and the cells get more or less bombarded with insulin to push the glucose into the cells. Insulin and glucose levels go through the roof, but the cells still don’t get all the sugar they need for energy production. The excess sugar that couldn’t enter the cells, gets stored inside the liver as glycogen or is converted into fat and stored in the body’s adipose tissue. Common symptoms of insulin resistance are fatigue, cravings and weight gain.


Insulin’s Role in Fat Storage and How our Body Burns Fat

Moving on, let’s explore insulin’s second metabolic role in more detail: Insulin as a fat storage hormone. Weight gain in women with PCOS is mainly associated with elevated insulin levels, which plays a major role in fat metabolism. When insulin is high, our body easily stores fat and makes it impossible for it to be broken down. However, the opposite applies as well: When insulin levels are low, our body can break down fat. But in order for fat burning to happen, both insulin and sugar levels, including the glycogen storages inside the liver need to be low, since our body will only switch to burning fat as fuel, once glucose is not available anymore.


Insulin and Its Role in Inflammation

Besides playing a vital role in fat and sugar metabolism, insulin is a pro-inflammatory hormone. Inflammation is a natural process occurring inside of our body. It’s a response of our immune system to possible threats. Chronically elevated insulin levels can lead to chronic inflammation over time, leading to chronic pain, fatigue and auto-immune diseases such as Hashimoto’s thyroiditis, which is characterized by a low-functioning thyroid and very common in women with PCOS.


How Elevated Insulin Levels Drive PCOS

Now, let’s have a closer look at how elevated insulin levels drive and worsen Polycystic Ovarian Syndrome. Insulin affects PCOS by indirectly increasing testosterone levels, which drives symptoms such as anovulation and missing periods, acne, hair loss and hirsutism. Our ovaries are very sensitive to insulin and have cells with insulin receptors. Increased levels of the hormone insulin cause the ovaries to produce more testosterone. Another organ that reacts to insulin is the liver. When insulin is high, the liver produces less Sex Hormone Binding Globulin, SHBG in short, which leads to an increased amount of free floating testosterone and estrogen inside the blood stream. Inflammation has a similar effect on the ovaries and can lead to higher testosterone levels as well. Since insulin is a fat storage hormone, it can lead to obesity, which in turn can worsen PCOS because our adipose tissue is hormonally active. About 50% of estrogen is converted from testosterone and DHEA inside the fat cells. If estrogen levels are high in women with PCOS, it can put a halt on the maturation of follicles inside the ovaries and ovulation does not happen.


The Effects of a Low-Carb Dieting Approach on PCOS

When talking about a low-carb diet, it means that you are only getting 10 to 15% of your daily caloric intake from carbohydrates. For women with PCOS suffering from underlying thyroid conditions or adrenal diseases, a moderate carbohydrate intake of about 15 to 30% is recommended. In fact, when starting to reduce carbohydrates, I usually recommend my clients to start with about 30%. The reason why a low to moderate carbohydrate diet works for women with PCOS, is because it keeps blood sugar levels balanced. Consumption of small amount of carbohydrates with every meal combined with lean protein, healthy fats and fiber leads to a slow absorption of small amounts of glucose into the blood stream, thus keeping blood sugar and insulin levels low, which can lead to decreased amounts of free testosterone in the blood stream and less symptoms associated with it, such as acne, hair loss or excess hair growth. Lowering testosterone levels can help you restore ovulation and get your periods back. Low insulin levels also allow your body to burn fat, given that the glycogen storages in the liver are empty and thus favoring weight loss. Losing just about 6% of a woman’s body weight, can help improve PCOS symptoms such as lack of ovulation, acne, hair loss and excess hair growth. Keeping insulin in check also means reducing inflammation inside the body, which is another main driver of PCOS.

So, to recap, it’s important to keep the hormone insulin low since it can drive excess testosterone production, obesity and inflammation. In order to keep insulin in check, it’s important to balance blood sugar levels by following a low- to moderate-carb dieting approach.

I hope you enjoyed this blog post. In part 3 of this weight loss series, we’ll explore what it means to eat for blood sugar balance, in more detail. I can’t wait to share with you!

Have you tried a low-carb diet in the past and has it helped you with managing PCOS? I would love to hear from you in the comments below.

Sending you my love,


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Nadine is a PCOS health coach, hormone expert, and woman with PCOS who helps other cysters around the world manage their symptoms naturally, lose weight and increase fertility.