Type 2 Diabetes

Type 2 Diabetes

What Is Insulin Resistance? Causes, Symptoms, Diagnosis, Treatment, and Prevention

Valencia Higuera
By Medically Reviewed by 
Reviewed:
Medically Reviewed
What-Is-Insulin-Resistance graphic
The hormone insulin helps keep blood sugar levels steady. But when insulin resistance occurs and the body is not able to keep up with increased insulin demands, glucose accumulates in the blood, either leading to or exacerbating prediabetes and type 2 diabetes.iStock
Carbohydrates — sugars and starches found in many foods — are a main source of fuel for your body. Your digestive system breaks down carbs into glucose, or sugar, which is then released into your bloodstream. And with the help of insulin, glucose can be absorbed into the cells of your body to be used for energy or storage.

But if you have insulin resistance, your cells will have trouble absorbing this glucose, and your body will require more insulin to function properly.

It is possible to overcome insulin resistance. But before you can deal with this problem, you must understand what insulin is and how insulin affects control of blood glucose.

What Is Insulin?

Insulin is a hormone produced by your pancreas that delivers glucose in your blood to cells in the muscles, liver, and fat, where it’s used for energy.

This hormone is also important because it stops sugar from accumulating in your bloodstream. The more you eat, the more insulin your body releases to regulate your blood sugar and keep it within a healthy range.

How Insulin Resistance Affects Blood Sugar Levels

Although the production and release of insulin is a natural metabolic response after eating, some people don’t use insulin properly.

To receive energy, your cells, fat, and muscles must be able to absorb the glucose in your bloodstream. To help you maintain a normal blood sugar level, your pancreas compensates for resistance by releasing more insulin. If your pancreas cannot meet the increasing demands, sugar accumulates in your blood, causing high blood sugar.

Common Questions & Answers

What causes insulin resistance?
The exact cause of insulin resistance isn’t known, but it’s been linked to family history, obesity, a diet high in sugar and calories, chronic stress, a sedentary lifestyle, steroid use, and having Cushing’s disease or polycystic ovary syndrome (PCOS).
Is there an insulin resistance diet?
Eating a diet that’s high in calories and sugar has been shown to increase insulin resistance, while following a low-carb diet can reduce insulin resistance and improve the way your body deals with glucose.
How can I prevent insulin resistance?
You can prevent or improve insulin resistance by making some lifestyle changes, including losing weight, quitting smoking, changing medication, eating a healthy diet, prioritizing sleep, and managing stress levels.
Does insulin resistance mean I have diabetes?
Not necessarily. However, if you don’t take steps to reduce the insulin resistance, it can develop into prediabetes or type 2 diabetes.
How is insulin resistance treated?
There’s no specific medication to treat insulin resistance, though diabetes medication can be beneficial. Lifestyle changes, including following a healthy diet and exercise routine, can also help.

Signs and Symptoms of Insulin Resistance

Insulin resistance may not cause any noticeable symptoms, so you can have insulin resistance and not know it. Symptoms don’t usually occur until you develop prediabetes or type 2 diabetes.

If your blood sugar level becomes elevated and you have prediabetes or diabetes, symptoms may include increased thirst and hunger, tiredness, and blurry vision.

Insulin resistance can also cause the formation of dark patches on the neck, groin, and armpits called acanthosis nigricans.

You may also have tingling sensations in your hands or feet.

Causes and Risk Factors of Insulin Resistance

Although the exact cause of insulin resistance is unknown, certain factors have been linked with this condition. These include:

Some people are also at a higher risk for developing insulin resistance. These include people:

  • With a family history of type 2 diabetes
  • With a personal history of gestational diabetes
  • Over the age of 45
  • Who are Hispanic, African American, Native American, or Asian American
  • With a waist circumference larger than 40 inches (men) or larger than 35 inches (women)
  • With a history of high blood pressure (hypertension) or high triglycerides

The risk factors for insulin resistance are similar to the risk factors for prediabetes and type 2 diabetes. But lifestyle changes can help your body use insulin properly, which can reduce your risk of diabetes.

How Is Insulin Resistance Diagnosed?

Although insulin resistance doesn’t usually have symptoms, your doctor may recommend testing your blood sugar if you have risk factors for this condition, such as obesity, a sedentary lifestyle, or high blood pressure.

This involves a series of tests that are the same for diagnosing prediabetes and type 2 diabetes.

Hemoglobin A1C Test This blood test measures your average blood glucose level over a period of two to three months. This test can determine your blood sugar level and help your doctor assess how well you’re managing diabetes. A normal A1C test result is under 5.7 percent, while results between 5.7 and 6.4 percent are prediabetes, and results equal to or above 6.5 percent are type 2 diabetes.

You’ll repeat testing at different intervals over three months to confirm an initial diagnosis.
Fasting Plasma Glucose (FPG) You will not consume food or liquids for at least eight hours, and then your doctor will draw blood to measure your blood sugar level after fasting. If you have an elevated blood sugar, you’ll return a few days later to repeat the test. A repeatedly high level can indicate either prediabetes or diabetes. A number under 100 milligrams per deciliter (mg/dL) is normal, a number between 100 to 125 mg/dL signals prediabetes, and a number greater than 125 mg/dL signals type 2 diabetes.

Oral Glucose Tolerance Testing (OGTT) Your doctor measures your blood glucose level, gives you a sugary liquid to drink, and then repeats the test two hours after you drink the liquid. If after two hours your blood sugar level is less than 140 mg/dL, your blood glucose level is considered normal. A number between 140 and 199 mg/dL is considered prediabetes, and a number 200 mg/dL or higher signals type 2 diabetes.

Insulin Resistance Screening

While you typically wouldn’t be screened for insulin resistance, you would be tested for high blood sugar if you have diabetes risk factors or symptoms.

In these cases, your doctor may perform a random blood sugar test at any time of day. Results over 200 mg/dL may confirm diabetes.

Prognosis of Insulin Resistance

There are varying degrees of insulin resistance, and people with severe insulin resistance have a harder time managing their diabetes.

But the good news is that lifestyle changes significantly improve insulin resistance.

Duration of Insulin Resistance

There’s no way to say exactly how long insulin resistance will last, but the sooner you address it and make necessary lifestyle changes, the more quickly insulin resistance will improve. Losing at least 5 percent of your body weight and exercising about 25 minutes a day for five days a week can help you avoid insulin resistance.

Insulin sensitivity may even start to improve after a few days of eating less.

Treatment and Medication Options for Insulin Resistance

Certain medications have been shown to make your body more sensitive to insulin.

Medication Options

There’s not a specific medication that’s approved to treat insulin resistance, but diabetes medication such as metformin (Metformin Eqv-Fortamet) and thiazolidinediones (TZDs) reduce insulin resistance and lower blood sugar.

Alternative and Complementary Therapies

Lifestyle changes, such as exercise and eating a healthy diet, may promote weight loss and metabolic improvements, thereby increasing insulin sensitivity.

Prevention of Insulin Resistance

Making lifestyle changes can help reverse insulin resistance so that your body can respond properly to insulin.

Lose weight. A study published in 2019 found weight loss improved insulin responsiveness and normalized blood glucose levels.

Focus on incorporating healthy foods you can eat long term and embracing activity. Do a moderate-intensity exercise, like brisk walking, for at least 150 minutes a week.

Choose activities that you find enjoyable, such as walking, biking, swimming, or playing sports. Losing as little as 10 to 15 pounds may help reverse and prevent insulin resistance.

Eat a low-carb diet. Reducing your intake of carbohydrates may also improve glucose metabolism and reduce insulin resistance. Other research, published in 2016, found that eating three low-carb meals in a 24-hour period could reduce post-meal insulin resistance by more than 30 percent. Study participants limited their carbohydrate intake to no more than 30 percent per meal.

Although more research is needed to confirm these results, eating a balanced diet that consists of moderate portions of carbohydrates and sugars may improve how your body uses insulin and reverse insulin resistance.
Change your medication with doctor supervision. You may have insulin resistance if you take steroid medication to treat pain and inflammation.

These drugs prompt the liver to release extra glucose, increasing the risk for steroid-induced diabetes. Lowering your dosage or slowly weaning yourself off steroids may improve insulin sensitivity. Speak with your doctor before modifying your medication.
Quit smoking. Giving up cigarettes may also reverse insulin resistance. According to a 2019 study, nicotine contributes to insulin resistance.

Get plenty of sleep. According to recommendations published in 2015, adults need between seven and nine hours of sleep a night for optimal health.

Not getting enough sleep may increase your risk for diabetes or make it harder to control.

Speak with your doctor if you’re having trouble sleeping. This may indicate a sleep disorder.
Manage stress well. When you’re under stress, your body produces higher amounts of cortisol, which is a stress hormone.

This hormone can make your muscles and cells resistant to insulin, resulting in higher blood sugar. As a result, chronic stress may increase your risk for prediabetes and type 2 diabetes.

Complications of High Blood Sugar Resulting From Insulin Resistance

The effects of insulin resistance on the body vary from person to person. Sometimes, the increased production of insulin by the pancreas is enough to overcome insulin resistance and normalize blood sugar levels. But other times, the pancreas is unable to produce sufficient amounts of insulin to overcome the resistance. This triggers high blood sugar (hyperglycemia) and, if A1C reaches a certain level, prediabetes and diabetes.

Additional health complications that can result from high blood sugar include:

  • Ketoacidosis and ketones
  • Skin complications
  • Heart disease
  • Kidney disease
  • High blood pressure
  • Stroke
  • Neuropathy or nerve damage
  • Retinopathy, vision loss, or eye complications

Research and Statistics: How Many People Have Insulin Resistance?

About one in every five American adults has insulin resistance.

Insulin resistance can advance to prediabetes, which affects more than 84 million — or about one in three — adults in the United States.

Finally, prediabetes can lead to type 2 diabetes, which affected about 11.3 percent of the U.S. population in 2019.

Insulin Resistance in the BIPOC Community

Certain races are more prone to insulin resistance. Non-Hispanic whites and African Americans had greater insulin sensitivity than East Asians and South Asians.

And people with an East Asian or African genetic background were found to be at a higher risk of type 2 diabetes than Caucasians.

The rates of being diagnosed with diabetes are:

  • 7.4 percent of non-Hispanic whites
  • 9.5 percent of Asian Americans
  • 12.1 percent of non-Hispanic blacks
  • 11.8 percent of Hispanics
  • 14.5 percent of American Indians/Alaskan Natives

Related Conditions and Causes of Insulin Resistance

Although insulin resistance can exist on its own without another diagnosis, it relates to certain health conditions, including the following:

Prediabetes

If your pancreas struggles to produce enough insulin to handle the glucose in your body, your blood sugar level can become mildly elevated, and you may develop prediabetes. This means your blood sugar is higher than normal but not high enough to be diagnosed with diabetes.

This condition — which affects about 84.1 million people — is a precursor to type 2 diabetes. Having prediabetes also is associated with an increased risk for heart disease, stroke, eye problems, neuropathy (nerve damage), and kidney disease.

Type 2 Diabetes

In the case of prediabetes, your pancreas works overtime to secrete enough insulin to regulate your blood sugar. But if your pancreas can’t keep up with the demand, insulin resistance can progress from prediabetes to type 2 diabetes. Most people diagnosed with prediabetes end up with type 2 diabetes within 10 years.

Metabolic Syndrome

Metabolic syndrome is also closely related to insulin resistance. Interestingly, metabolic syndrome isn’t a condition in itself but rather a collection of metabolic risk factors that can set the stage for type 2 diabetes and heart disease. Insulin resistance is included among these risk factors, along with high blood pressure, abnormal cholesterol levels, high triglycerides (a form of fat storage often related to lifestyle factors), and a large waist circumference.

Resources We Love

Favorite Org for Essential Information Regarding Insulin Resistance and Diabetes

American Diabetes Association (ADA)

Insulin resistance is a hallmark of diabetes, so make note of the ADA, an organization that educates the public about diabetes. The website offers a host of information, including tips on how to assess and lower your diabetes risk and resources for living with diabetes if you have been diagnosed, such as recipes and how to find a diabetes education program.

Favorite Resource for Diabetes Education

Joslin Diabetes

If insulin resistance has led you to be diagnosed with diabetes or you want to be educated if that day comes, enroll in a program led by Joslin Diabetes experts. The 12-week Why Wait program is designed to help you meet your weight goals, which could improve your body’s sensitivity to insulin.

Favorite Carb-Counting App

Carb Manager

Turn to this app to easily track your carb intake. Doing so is important for people dealing with insulin resistance, as following a low-carb diet has been shown to lead to improvements with the body’s insulin response.

Favorite Exercise App

Google Fit

If reversing insulin resistance is your goal, add exercise to your daily routine. Make sure you’re logging enough heart-pumping exercise by downloading Google Fit. The app will track your “Heart Points,” a feature that was developed alongside the American Heart Association. You’ll earn one Heart Point for every minute of moderate-intensity exercise. Your goal? Thirty minutes five days a week, all tracked within the app.

Favorite Low-Carb Meal Delivery Plan

Factor

One way to follow a very low-carb eating plan, such as the ketogenic diet, is to turn to a meal delivery service like Factor. Consider your needs, and choose your frequency of meals (4 to 18 meals a week) delivered right to your door. If keto represents a dramatic change in your usual eating style, which is the case for many people, consider working with a registered dietitian before diving in. And check with your healthcare team first if you’re on any medication or have already developed type 2 diabetes.

Editorial Sources and Fact-Checking

Show Less