If you have PCOS, you have probably heard the term insulin resistance many times. You may have also been told to cut back on carbohydrates. But what exactly is insulin resistance, why is it so closely linked to PCOS, and do you really need to go low carb?
Understanding what insulin resistance is and how it works can help you better understand PCOS and its effects on the body. In this article, I will explain what insulin resistance is, why it is so common in PCOS, and why it matters for your long term health.
What happens in the body after you eat?
When you eat a meal containing carbohydrates, your body breaks those carbohydrates down into glucose, which enters the bloodstream. As blood glucose levels rise, the pancreas releases a hormone called insulin.
One of insulin’s main jobs is to move glucose from the bloodstream into the cells where it can be used for energy. You can think of insulin as a key that unlocks the doors to the cells, allowing glucose to enter.
As glucose moves into the cells, blood glucose levels return to a normal range. The body works very efficiently to keep blood sugar tightly regulated. Meals that are higher in carbohydrates, especially refined or sugary carbohydrates, tend to raise blood glucose more quickly and trigger a larger insulin response.
Protein has a smaller effect on blood glucose levels, while fat has very little direct effect. This is the normal process of blood sugar regulation. However, when someone has insulin resistance, this process does not work as efficiently.
What is insulin resistance?
As mentioned above, blood sugar rises and insulin is released after eating a meal that contains carbohydrates. The pancreas produces insulin, which tries to open the cell doors so glucose can move out of the bloodstream and into the cells.
However, with insulin resistance, the cells do not respond as well to insulin. You can visualize this as a key getting stuck in the lock and being unable to fully open the door.
Because the cells are resistant to insulin, the pancreas has to produce larger amounts of insulin in order to move glucose into the cells. As a result, insulin levels in the blood become elevated. This is called hyperinsulinemia.
Over time, this can create a vicious cycle. The body produces more insulin to compensate, and high insulin levels can make the cells even less responsive to insulin.
High levels of insulin circulating in the body can affect many systems and contribute to several health problems. In simple terms, insulin resistance is a warning sign that without intervention and lifestyle changes, someone may go on to develop prediabetes or type 2 diabetes.
Can you be insulin resistant if you have normal blood sugar?
This is one of the questions I get asked most often: If your blood sugar is normal, can you still have insulin resistance?
Yes. Normal blood sugar does not necessarily mean that insulin levels are normal. The body works very hard to keep blood glucose within a healthy range. In the early stages of insulin resistance, the pancreas compensates by producing more insulin to keep blood sugar normal. As a result, someone may have elevated insulin levels even though their blood sugar appears normal on routine lab tests.
Over time, however, the pancreas may no longer be able to keep up with the increased demand for insulin. When this happens, blood sugar levels begin to rise, which can lead to prediabetes and eventually type 2 diabetes.
Because insulin resistance can be difficult to detect with standard lab tests, it is often missed in the early stages. If you would like to learn more about how insulin resistance can be evaluated, you can read my article on How to Test for Insulin Resistance.
Women with PCOS have a higher risk of developing these conditions. Research suggests that up to 40 percent of women with PCOS develop prediabetes or diabetes by age 40, and about 50 percent by age 50.
What causes insulin resistance?
Researchers don’t know exactly what causes insulin resistance. However we know there are risk factors. Some modifiable, while others are not. Here is a list of risk factors for insulin resistance:
- Genes
- PCOS
- Overweight or obese. Being obese triples your risk for insulin resistance. Some researchers have theorized that the extra fat tissue in the body may cause inflammation, physiological stress, or other changes in the cells that contribute to insulin resistance reference
- Excess fat around the waist presents an even greater risk. This is because fat secretes hormones and other substances that may interfere with insulin reference
- Physically inactive. Not getting enough exercise can affect the way insulin regulates glucose
- Sitting too much – especially for prolonged periods of time
- Aging can increase insulin resistance because the cells don’t work as well.
- Chronic stress with can lead to elevated cortisol levels
- Medications (i.e. cortisone and thiazide diuretics)
- Pregnancy
- Diseases (Cushing’s syndrome, growth hormone excess)
- Certain endocrine disrupting chemicals, such as BPA, may play a role.
- Inflammation
- Inadequate sleep
Insulin resistance and PCOS
Having PCOS is a major risk factor for insulin resistance. As mentioned earlier, insulin resistance is believed to play an important role in the development of PCOS. So does every woman with PCOS have insulin resistance? No, but many do. The challenge is that insulin resistance can be difficult to diagnose with standard medical tests, which makes it hard to estimate exactly how many women with PCOS are affected.
The 2023 International Evidence Based Guideline for the Assessment and Management of Polycystic Ovary Syndrome estimates that approximately 75 to 95 percent of women with PCOS have insulin resistance, depending on how it is measured and the population studied.
Other research estimates that 50 to 70 percent of women with PCOS are insulin resistant. Weight also plays a role. Studies suggest that:
- About 70 to 80 percent of women with PCOS who have obesity are insulin resistant
- About 20 to 25 percent of lean women with PCOS may also have insulin resistance
This suggests that PCOS may involve an intrinsic insulin resistance, meaning the condition itself affects insulin signaling independent of body weight. Lifestyle factors such as inactivity, chronic stress, poor sleep, and diet may further worsen insulin resistance. There are also different degrees of insulin resistance. Some women may experience mild insulin resistance with few symptoms, while others may have more significant metabolic changes.
In general, the more insulin resistant someone is, the greater the risk of developing health complications.
Why is insulin resistance dangerous?
Having insulin resistance or high levels of insulin circulating in the blood can affect many systems in the body and contribute to a variety of health issues. These can range from mild symptoms to more serious long term health risks.
These may include:
- Carbohydrate cravings
- Energy drops
- Mood disorders and increased rates of depression
- Worsened symptoms of PCOS
- Weight gain and difficulty losing weight
- High triglycerides
- Chronic inflammation
- Metabolic dysfunction associated steatotic liver disease (formerly called non alcoholic fatty liver disease)
- Elevated blood pressure
- Increased risk of cardiovascular disease
- Increased risk of prediabetes and type 2 diabetes
The American Diabetes Association estimates that up to 50 percent of people with insulin resistance and prediabetes will develop type 2 diabetes if lifestyle changes are not made.
Bottom line
Insulin resistance affects many women with PCOS to varying degrees and is believed to play an important role in the condition, along with other factors. The exact cause is not fully understood, but there appears to be an intrinsic insulin resistance associated with PCOS. This may be compounded by factors such as weight gain, inactivity, poor diet, stress, and inadequate sleep.
Insulin resistance is associated with several health risks, including an increased risk of prediabetes and type 2 diabetes. Because insulin resistance can be difficult to diagnose with standard medical tests, it is hard to determine exactly what percentage of women with PCOS are affected. However, it is likely that the majority of women with PCOS have some degree of insulin resistance.
The good news is that there are many things you can do to improve insulin resistance. Nutrition and lifestyle changes can play a major role in improving insulin sensitivity and reducing the health risks associated with PCOS. Stay tuned for a blog post on this!
If you would like personalized guidance on improving insulin resistance and managing PCOS, I can help. In my virtual nutrition practice, I work with women with PCOS to develop practical, sustainable nutrition and lifestyle strategies that support hormone balance, metabolic health, and long term wellness. You can learn more about working with me here.
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