Insulin resistance: Causes, signs and what to do about it

Insulin resistance is a hot topic right now and commonly surfaces in conversations around diabetes, weight management and PCOS. This makes perfect sense when you look at the current state of health in our country:

• 3% of the U.S. population has insulin resistance, and this increases seven-fold if you happen to have prediabetes or diabetes.
• If you’re overweight, especially if you have excess belly fat, you’re also more likely to be insulin resistant, kids included.
• If you’re a woman who’s had trouble getting pregnant, you might have what’s called polycystic ovary syndrome (PCOS)—up to 12% or 15 million American women do—and then you’re also more likely to be insulin resistant, doubling your risk of type 2 diabetes by age 40.

Bottom line: insulin resistance is something that impacts a lot of people. So, let’s talk about what it is, how to tell if you are insulin resistant and what to do about it.

What is insulin resistance?

When your body functions as it was designed to, the food that you eat is broken down into blood sugar. It then enters your bloodstream and signals your pancreas to make insulin so it can enter your muscles’ cells for all of its daily energy until the body signals back to the pancreas that it’s got enough.

As you edge closer to type 2 diabetes, these same cells stop responding to all of that insulin, leading to more blood sugars—aka high blood sugar levels—in the bloodstream. This is called insulin resistance. Insulin resistance is also known as impaired insulin sensitivity.

“It is as if insulin is ‘knocking’ on the door of muscle. The muscle hears the knock, opens up and lets glucose in. But with insulin resistance, the muscle cannot hear the knocking of the insulin (the muscle is ‘resistant’). The pancreas makes more insulin, which increases insulin levels in the blood and causes a louder ‘knock.’ Eventually, the pancreas produces far more insulin than normal and the muscles continue to be resistant to the knock. As long as one can produce enough insulin to overcome this resistance, blood glucose levels remain normal. Once the pancreas is no longer able to keep up, blood glucose starts to rise, initially after meals, eventually even in the fasting state.”

— MedicineNet medical dictionary, 2021

Is there a difference between insulin resistance & prediabetes?

Both conditions involve blood sugars getting out of balance. Prediabetes is a condition that occurs when your blood glucose levels are higher than they should be but aren’t yet high enough to be considered a type 2 diabetes diagnosis.

Prediabetes has two primary causes: either your pancreas isn’t able to make enough insulin or your insulin receptors stop responding properly to the insulin. This second case describes insulin resistance.

How you can tell if you’re insulin resistant

You can’t tell that you have insulin resistance by how you feel. For prediabetes or diabetes, there are the standard blood tests: A1C, fasting plasma glucose (FPG) and random plasma glucose (RPG). Though there are clinical tests for insulin resistance, the most accurate, gold standard measurement—the hyperinsulinemic-euglycemic glucose clamp technique—is complicated and used mostly for research.

Still, even without a test, the National Institutes of Health says there are genetic or lifestyle questions you can ask to evaluate your risk for insulin resistance. The more criteria you see, the more risk you have:

• Overweight or obesity?
• Age 45 or older?
• A parent, brother or sister with diabetes?
• African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander American ethnicity?
• Physical inactivity?
• Health conditions such as high blood pressure or abnormal cholesterol levels?
• A history of gestational diabetes?
• A history of heart disease or stroke?
• Smoking?
• Sleep problems like sleep apnea or regularly losing 1-3 hours of sleep per night?
• Polycystic ovary syndrome, also called PCOS?

There are also some telltale biological signs you can look for:

• A waistline over 40 inches in men and 35 inches in women
• Blood pressure readings of 130/80 or higher
• Fasting glucose level over 100 mg/dL
• Fasting triglyceride level over 150 mg/dL
• HDL cholesterol level under 40 mg/dL in men and 50 mg/dL in women
• Skin tags or patches of distinctive, dark, velvety skin called acanthosis nigricans

What insulin resistance means for your diabetes health

There are degrees of insulin resistance—the more resistant you are, the more work and the more insulin you’ll need to keep blood sugar levels in your normal or target range and keep any of a number of diabetes-related complications at bay. It’s also not just a hallmark of people with prediabetes or type 2 diabetes. While insulin resistance doesn’t cause type 1 diabetes, you can be insulin resistant if you have type 1 diabetes.

How to increase insulin sensitivity

We know that improved diet, increased exercise and weight loss lower blood glucose levels and help prevent the progression of prediabetes to diabetes. Research surmises that these same lifestyle changes also play an important role in improving insulin resistance, though it is “seldom restored to normal,” according to the American Diabetes Association. To date:

• No single eating pattern has been shown most effective in targeting insulin resistance, though a recent study of women who followed the plant-based Mediterranean diet reduced their risk of cardiovascular health problems, including factors such as insulin resistance, some by 25%.
• Though there aren’t medications approved to specifically treat insulin resistance, diabetes medications like metformin and thiazolidinediones (TZDs) are insulin sensitizers that lower blood sugar by reducing insulin resistance.
• Findings support behaviors like healthy eating, regular physical activity and quality sleep as key controllable behaviors associated with good insulin sensitivity, and, especially in combination, like losing weight and exercise, as dramatically improving insulin sensitivity compared to any one behavior alone.

So, ask your provider for a referral to a registered dietitian who can help you come up with a personalized plan to combat insulin resistance. For example, we can individualize a weight management meal plan for you, along with an exercise strategy that works for you.

The bottom line? Don’t give up

“While fighting an invisible foe can feel frustrating and discouraging, know that you are not alone. There are effective tactics to combat insulin resistance. Losing weight, exercising more or taking an insulin-sensitizing medication can help you get back to good blood sugar control and better health.”

– American Diabetes Association, 2021

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