Insulin Resistance and PCOS; What You Need to Know

Insulin Resistance

If you have PCOS, you’ve probably heard the words “insulin resistance” many times! But do you really understand what it means? Since insulin resistance may be at the root of PCOS, it’s helpful to understand what is it and what you can do about it. While nutrition is a major factor  in decreasing insulin resistance, there are numerous other lifestyle factors that help. Knowledge is empowerment! You can then come up with a practical plan to improve insulin resistance, which in turn will improve your symptoms of PCOS, fertility, help with weight management and overall health. So tune into this 3 part series on insulin resistance. Today is part one: insulin resistance and PCOS. I’ll give a detailed explanation on what insulin resistance is. In my upcoming blog posts, I’ll talk about how to diagnosis it and what to do about it. Read on …

PCOS and Insulin Resistance | Martha McKittrick Nutrition

lock and key in insulin resistance

What happens in the body after you eat?

Eating a typical meal will cause glucose levels to rise. The more carbs you eat, especially if sugary or processed,  the higher the blood sugar rises. Fat does not cause blood sugar to rise and protein has a minimal effect of raising blood sugar. The elevated blood sugar triggers the pancreas to produce a hormone called insulin. One of insulin’s main jobs is to move glucose from the bloodstream into the cells so it can be used for energy. It can help to visualize insulin acting like a “key” unlocking the doors to the cells, letting in the glucose. As glucose is taken up by the cells, blood glucose levels fall into a normal range. The body is very efficient at keeping the blood sugar in a normal range. The more carbs you eat, the higher your blood sugar rises and the more insulin you make. The “key” opens the cell doors and blood sugar is brought to a normal range. That’s the normal process. But what happens in insulin resistance is different!

What is insulin resistance?

As mentioned above,  blood sugars rises and insulin is produced after eating a high carb meal. The pancreas makes insulin which tries to open the cell doors to get the sugar out of the blood. However the cells have become resistant to the insulin. Visualize a “key” getting stuck in the door and being unable to open it. The pancreas then has to secrete greater amounts of insulin to force the cells to take in the glucose. So now there are high levels of insulin in the blood (called hyperinsulinemia). This makes the cells even more resistant to the insulin, so MORE insulin needs to be secreted. It turns into a viscous cycle! The problem is that high levels of insulin in the body can wreak havoc in the body.

In a nutshell: having insulin resistance is a warning that, without intervention and effective lifestyle changes, someone with may go on to develop prediabetes and  type 2 diabetes.

Can you be insulin resistant if you have normal blood sugar?

I get asked this question all the time. If your blood sugar is normal, can you still be insulin resistant? Absolutely!  Normal blood sugar does not mean that you don’t have high levels of insulin in your blood. The body is so intent on keeping blood sugar in a normal range, that it pumps out as much insulin as it can to keep blood sugar normal. Medical tests aren’t very good at diagnosing this. However, eventually the pancreas can no longer produce enough insulin to do this, so blood sugar starts to creep up. This can turn into prediabetes and then diabetes. This is why up to 40% of women with PCOS get prediabetes or diabetes by age 40, and 50% 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.
  • Stress
  • 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 previously, it’s believed that insulin resistance is at the root of PCOS. So is every woman with PCOS insulin resistant? No, but many are. The problem is that it’s difficult to diagnosis insulin resistance with medical tests. Therefore it’s also difficult to estimate what percentage of women with PCOS are insulin resistant.
-This reference estimates that 50 to 70% of women are insulin resistant.
– Some PCOS experts, including Dr. Felice Gersh, feels almost all women with PCOS have some degree of insulin resistance.
– And this reference  states that  70–80% of women who are obese (BMI > 30)  are insulin resistance as well as  20–25% of women who are lean (BMI<25).

In general, the more overweight you are, the greater the likelihood that you’ll be insulin resistant. However since lean women can also be insulin resistant, there is believed to be an intrinsic insulin resistance in women with PCOS. The factors above (i.e. inactivity, stress) could compound it. And there are varying degrees of insulin resistance. A woman who is very overweight, has great difficulty losing weight and experiences many symptoms of PCOS likely is much more insulin resistance than a “lean” woman with PCOS who stores a little extra fat in the abdominal area, has irregular periods and some acne. In general, the more insulin resistant you are, the greater risk you have for the following health considerations.

Why is insulin resistance dangerous?

Having insulin resistance or high levels of insulin in your blood can have numerous consequences on your health, ranging from mild to very serious. These include:

  • Carb cravings
  • Energy drops
  • Mood disorders and increased rates of depression
  • Worsened symptoms of PCOS
  • Weight gain and difficulty losing weight
  • High triglycerides
  • Inflammation
  • Non-alcoholic fatty liver disease (NAFLD),
  • Increased risk of prediabetes and type 2 diabetes. The American Diabetes Association (ADA) estimates that up to 50 percent of people with insulin resistance and prediabetes will develop type 2 diabetes if they don’t make lifestyle changes. reference 
  • Elevated blood pressure
  • Increased risk of vascular diseases such as heart disease reference

Bottom line

Insulin resistance affects the majority of women with PCOS to varying degrees and is believed to be at the root of PCOS (along with other factors).  The exact cause is not known, however there is believed to be  an intrinsic insulin resistance unique to PCOS. This is likely compounded by issues including weight gain, inactivity, poor diet, stress, inadequate sleep, etc. Insulin resistance is associated with health risks, including increased risk of diabetes. We don’t know exactly what percentage of women with PCOS are insulin resistant due difficulties in diagnosing it with our current medical tests. It is likely that the majority of woman with PCOS have some degree of insulin resistance.  The more insulin resistant you are, the greater the health risks. My goal is not to cause alarm with this blog post, but rather to help educate you on what insulin resistance is. And more importantly, what you can do about it. The good news is that diet and lifestyle can play a major role in decreasing insulin resistance, thereby decreasing symptoms of PCOS and associated health risks.

Stay tuned for the next two blog posts in this series:
How to diagnose insulin resistance
How to decrease insulin resistance

I’d love you to send in your questions. I may incorporate them into the next blog posts!



I especially love problem-solving, whether it’s helping women defeat issues plaguing them for years, helping a busy executive find practical ways to get heart healthy, or providing tips to help you reverse diabetes. That’s why I’m on a constant quest to expand my knowledge by staying on top of the latest research.

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