What Is Insulin Resistance? Symptoms, Causes, and Diet for Reversal

The body naturally produces insulin to help keep blood sugar (also called “glucose”) within safe levels. But sometimes, your body doesn’t respond to the effects of insulin. When this happens, it’s called insulin resistance.

Here, we’ll discuss what insulin resistance is, how it can cause complications like Type 2 diabetes, and how you can prevent (or even reverse) it with lifestyle changes.

What is insulin resistance?

Insulin resistance happens when your body’s cells become resistant to the effects of insulin. When this happens, your body is no longer able to regulate its energy supply. This leads to a domino effect that looks something like this:

1. Glucose doesn’t get into your cells, where it’s needed for energy.

2. Instead of being stored for later, extra glucose starts to pile up in your blood.

3. The pancreas tries to fix this by releasing more insulin, in an attempt to process the excess glucose.

4. Eventually, the pancreas can’t keep up, and blood glucose levels continue to rise unchecked.

Promotional Disclosureinfo_outlined

SPECIAL OFFER

Save on popular GLP-1 Agonists

Take control of your health. With GoodRx, you may be eligible to save even more on popular treatments.

Get Savings

The health complications of insulin resistance are due to the combination of high blood glucose and high insulin levels.

What exactly is insulin?

Insulin is a hormone that regulates metabolism. More specifically, it helps your body balance its main source of energy: glucose. Here’s how it works:

1. Insulin is made by an organ called the pancreas, which sits behind your stomach. The pancreas releases insulin into your bloodstream after you eat or when your blood glucose levels are high. 

2. The burst of insulin sends the glucose you’ve just absorbed from your meal into cells, where it’s needed for fuel. Any extra glucose is stored in muscle cells for later.

3. Both of these insulin functions (fueling your cells and storing leftovers) help keep glucose levels steady in your blood. 

When this system is working properly, your blood glucose levels stay within a healthy range all day, whether you’ve just eaten or not. 

What causes insulin resistance?

The exact cause of insulin resistance isn’t fully known. But there are many things that can increase a person’s risk, including stress and PCOS. 

Some of the most common risk factors include:

• Having a body mass index (BMI) that’s considered overweight or obese, especially with excess abdominal (belly) fat 

• Being part of a Black, Asian, or Hispanic ethnic groups

• Having a family history of insulin resistance or diabetes 

• Having diabetes in pregnancy (gestational diabetes)

• Having polycystic ovary syndrome (PCOS) 

• Eating a diet high in carbohydrates or sugar

• A sedentary lifestyle

• Having a high blood pressure, heart disease, or a history of stroke 

• Having abnormal cholesterol levels

• Taking steroid medications 

• Living with chronic stress

EXPERT PICKS: WHAT TO READ NEXT

• Exercise can help improve insulin resistance. These exercises lower blood sugar and improve your energy levels.

• Did you know that some common medications can raise your blood sugar? Here are common prescriptions that can cause hyperglycemia (high blood sugar).

• Polycystic ovary syndrome (PCOS) is a common cause of insulin resistance. This dietary advice can help regulate hormones and ease PCOS symptoms.

What are the signs and symptoms of insulin resistance?

In the early stages of insulin resistance, there are usually no symptoms. But over time, the combination of high blood glucose, high insulin levels, and insulin resistance can lead to complications in multiple body systems.

The symptoms someone has will largely depend on what’s causing their insulin resistance and what health issues develop because of it.

Some people may have one or more of these subtle signs: 

• Irregular menstrual cycle

• Excessive body hair (hirsutism)

• Dark, thick patches of skin in skin folds or creases (acanthosis nigricans)

As glucose levels build up in the blood, your body responds by trying to remove it. It tries to store it in your liver and muscles. And then your body stores it as body fat. This is why weight gain can also be a sign of insulin resistance. 

If you have experienced any of these symptoms, speak with a healthcare professional. They can help determine if you need to be checked for signs of insulin resistance.

What are the complications of insulin resistance?

Even though insulin resistance often has no early symptoms, it can affect your body in many serious ways. Most importantly, it’s a main cause of: 

• Prediabetes 

• Type 2 diabetes

• Metabolic syndrome

• Weight gain

• Coronary artery disease

• Fatty liver disease

Metabolic syndrome

This is one of the most severe complications of insulin resistance. Metabolic syndrome is a chronic condition that includes:

• High cholesterol

• High blood pressure

• High blood glucose levels (which can lead to prediabetes and Type 2 diabetes)

• Excess body fat around your waist

Metabolic syndrome involves many different body systems and can cause health problems like heart disease, diabetes, and stroke. 

Prediabetes and Type 2 diabetes

Prediabetes and Type 2 diabetes develop when high blood glucose levels persist over time. You can have blood glucose that’s higher than what’s considered safe and have no symptoms. This is often the case if you have prediabetes. In the U.S., roughly 4 in 10 adults over the age of 18 have prediabetes.

If left untreated, prediabetes can progress to Type 2 diabetes. Type 2 diabetes is diagnosed when blood glucose levels go even higher than in prediabetes.

Prediabetes and Type 2 diabetes are especially serious effects of insulin resistance. That’s because they increase your risk of complications, including:

• Heart disease

• Heart attack

• Stroke

• Kidney damage

• Eye damage

• Nerve damage

Is there a test to diagnose insulin resistance?

Unfortunately, there isn’t a simple test to screen for insulin resistance. But healthcare professionals can use a blood glucose test or a hemoglobin A1C test to check if you’re at risk for prediabetes or Type 2 diabetes.

In the early stages of insulin resistance, blood sugar levels may still appear normal. This means blood glucose or hemoglobin A1C tests aren’t always a reliable test of insulin resistance. Instead, your healthcare team will look at a mix of your symptoms, blood test results, and a physical exam to determine if you’re showing signs of insulin resistance. 

Some signs that may lead a healthcare professional to consider insulin resistance include:

• A larger waist circumference

• Elevated fasting glucose or A1C

• High low-density lipoprotein (LDL), triglycerides, or total cholesterol

• High blood pressure

• Elevated fasting insulin levels (rarely tested outside of research)

• Skin changes (like dark patches, rashes, or thickened skin)

• Symptoms of polycystic ovary syndrome (PCOS)

Can you reverse insulin resistance?

Yes. On the bright side, lifestyle changes can help improve insulin sensitivity — and may even reverse its effects.

Insulin resistance and diet

Carefully choosing what you include in your diet is an important way to help with insulin resistance and to avoid high blood sugar. The American Diabetes Association (ADA) often recommends talking with a professional, like a dietician, to improve your eating habits if you have prediabetes or diabetes.

Diets that are high in protein and low in carbohydrates are recommended. That’s because protein helps keep your blood glucose levels stable. High-carbohydrate diets can cause spikes in blood glucose levels that only make insulin resistance worse. 

Having insulin resistance doesn’t necessarily mean you have diabetes, but following a meal plan recommended by the ADA can help improve insulin sensitivity.

If you’re eating to reduce your insulin resistance, stick to a diet that’s high in protein and low in sugar. This can include foods like:

• Meats, poultry (like chicken and eggs), and fish

• Low-fat dairy products (like low-fat yogurt and cheese)

• Nuts 

• Vegetables 

• Whole grains

Insulin resistance and weight loss

Managing your weight through exercise and a nutritious diet can help your body respond better to insulin. Even small changes can help reverse insulin resistance. If you continue these habits over time, you can prevent or delay diabetes.

Here are some helpful goals for losing weight and lowering insulin resistance:

1. Engage in at least 30 minutes of physical activity most days of the week. Exercise is one of the fastest and most effective ways to reverse insulin resistance.

2. Eat a balanced diet that focuses on vegetables, proteins, and low-fat dairy. Moderating your carb intake can help with both weight management and insulin resistance.

3. Belly fat is closely linked to insulin resistance and heart disease. Losing weight around your abdomen not only improves insulin sensitivity but also lowers your risk of heart disease. Avoiding a sedentary lifestyle and engaging in consistent exercise has been shown to decrease excess weight in the midsection.

Keep in mind that many “fad diets” promote losing weight quickly through diet or exercise patterns that aren’t sustainable. The best way to lower your risk of insulin resistance is by making small, consistent changes in your diet and exercise regimen that you can stick with for the long run.

Frequently asked questions

Why trust our experts?

Written by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

Reviewed by:

Frank Schwalbe, MD

Frank Schwalbe, MD, is an assistant professor of anesthesiology at the Yale School of Medicine. He has practiced anesthesiology for 30 years.

Our editorial standards

Meet our experts