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Insulin Resistance – What You Need to Know

Medically Reviewed by Jabeen Begum, MD on April 22, 2024
Written by Stephanie Booth
9 min read

Insulin resistance is when cells in your muscles, fat, and liver don’t respond well to insulin, a hormone made by your pancreas that helps manage your blood glucose (blood sugar). Sometimes, insulin resistance is a short-term condition. But if left untreated for a long time, it could turn into diabetes.

Your body's main source of fuel is glucose, which it gets by breaking down the food you eat. Once glucose enters your bloodstream, insulin helps it get into your cells, where it's either used or stored for later. That signals your pancreas to stop making insulin.

But if you have insulin resistance, this process doesn't work well. Your cells aren't letting glucose in when insulin "asks" them to. As a result, more and more blood glucose piles up in your bloodstream. And your pancreas keeps making insulin.

For a while, your pancreas may be able to make so much extra insulin that your cells open up and let in glucose the way they're supposed to. That will keep your blood sugar within a normal range. But over time, your cells may become more insulin resistant and your blood glucose levels could keep rising.

Insulin resistance vs. diabetes

Insulin resistance and diabetes are related but not the same.

If you have insulin resistance, your blood sugar is still within a normal range.

Prediabetes usually happens to people who have some insulin resistance. Your blood sugar is higher than normal, but still not high enough for diabetes.

Insulin resistance and prediabetes can both lead to type 2 diabetes. So much glucose stays in your bloodstream, you will need medication to treat it.

You can't tell that you have insulin resistance by how you feel. You'll need to get a blood test that checks your blood sugar levels.

Likewise, you won’t know if you have most of the other conditions that are part of insulin resistance syndrome (high blood pressure, low "good" cholesterol levels, and high triglycerides) without seeing your doctor.

Some signs of insulin resistance include:

  • A waistline over 40 inches in men and 35 inches in women
  • Blood pressure readings of 130/80 or higher
  • A fasting glucose level over 100 milligrams per deciliter (mg/dL)
  • A fasting triglyceride level over 150 mg/dL
  • An HDL cholesterol level under 40 mg/dL in men and 50 mg/dL in women
  • Skin tags
  • Patches of dark, velvety skin under your arms or on your neck (acanthosis nigricans)
  • Damage to tiny blood vessels in the backs of your eyes, which can lead to a condition called retinopathy

 

 

Experts still don't fully understand what causes insulin resistance and prediabetes.

Things that can make this condition more likely include:

  • Having excess weight, especially belly fat
  • An inactive lifestyle
  • A diet high in carbohydrates
  • Having gestational diabetes
  • Health conditions (like nonalcoholic fatty liver disease ) 
  • A family history of diabetes
  • Smoking
  • Certain racial or ethnic backgrounds: You are more likely to become insulin resistant if you're Black, Asian American, or Hispanic/Latino. Indigenous people from Alaska, the continental U.S., and the Pacific Islands are also at high risk.
  • Age: It’s more likely after 45.
  • Hormonal disorders like Cushing’s syndrome , acromegaly, and hypothyroidism
  • Medications like steroids, some HIV treatments, and certain blood pressure medicines
  • Inherited conditions including myotonic dystrophy and inherited lipodystrophy
  • Sleep conditions like sleep apnea

Insulin resistance and PCOS

Polycystic ovary syndrome (PCOS) affects as many as 15% of people who are assigned female at birth (AFAB). It's one of the most common causes of infertility. 

If you have PCOS, you have higher-than-usual amounts of a hormone called androgen. This can make it hard for you to get pregnant. It also causes other symptoms, like acne and thinning hair. Most people with PCOS are also insulin resistant. 

The link between insulin resistance and PCOS is still unclear, but it's being studied. Your family history may play a part, since you're more likely to have PCOS if your mother or sister has it or type 2 diabetes. Excess weight can also be a factor.

Insulin resistance test

There isn't one specific test that checks for it. To figure out if you have insulin resistance, your doctor will rely on a combination of the following:

Questions. For instance, they’ll want to know about your family's health history.

Physical exam. They’ll weigh you and check your blood pressure.

Fasting plasma glucose test. This blood test measures your blood sugar after you haven’t eaten for at least 8 hours.

Oral glucose tolerance test. First, you'll take the fasting glucose test. Then you'll drink a sugary solution. Two hours after that, you'll take another blood test.

Hemoglobin A1c test. This blood test shows your average blood sugar level for the past 2 to 3 months. Doctors use it to diagnose prediabetes or diabetes. You may need to take the test more than once to confirm the results.

Lipid panel. Lipids are fatty compounds in your blood, like 'bad" LDL and "good" HDL cholesterol and triglycerides. A blood test can check your levels. High triglycerides and low "good" cholesterol have been linked to insulin resistance and type 2 diabetes.

If your pancreas can't produce enough extra insulin to make up for your insulin resistance, your blood sugar levels could rise until you have prediabetes. 

You should be screened starting at age 35. If you're carrying extra weight or have other risk factors for diabetes, your doctor may screen you sooner. If you had gestational diabetes during a pregnancy, you should have a test at least every 3 years.

These blood test results signal that you have prediabetes:

  • Fasting plasma glucose test: 100-125
  • Oral glucose tolerance test: 140-199 after the second test
  • A1c results of 5.7% to 6.4%

If you do have prediabetes, you'll probably need to repeat this lab work at least once a year so your doctor can keep an eye on your blood glucose levels. If you aren’t able to manage them, they'll keep going up. 

You’ll be diagnosed with type 2 diabetes if your test levels reach:

  • Fasting plasma glucose test: 126 or higher
  • Oral glucose tolerance test: 200 or higher after the second test
  • A1c results of 6.5% or above

The goal of insulin resistance treatment is to lower your blood sugar levels and prevent type 2 diabetes. 

Medication for insulin resistance

 There's no medicine that can cure insulin resistance. But your doctor may prescribe drugs to treat other health issues you have, like high blood pressure or high LDL ("bad") cholesterol.

If you're at increased risk of diabetes, you might also get a medication called metformin (Fortamet, Glucophage, Glumetza, Riomet). It's usually prescribed to people with diabetes to help keep blood sugar in check.

Reversing insulin resistance

Lifestyle changes like these can often help reverse insulin resistance.

Exercise. Being active improves how well your body uses insulin. Find an activity you enjoy so you're more likely to do it often. Aim for at least 30 minutes of moderate activity (like brisk walking) 5 or more days a week. Just starting out? Work up to that.

Get to a healthy weight. Losing as little as 5% to 7% of your weight can really lower your risk of type 2 diabetes. If you're not sure how to reach a weight loss goal, ask your doctor. You may also want to talk with a nutritionist and a certified personal trainer.

Eat fewer processed foods. While no foods are "bad" or off-limits, try to cut back on refined carbohydrates (like packaged baked goods), which tell your body to make more insulin.

Manage your stress. Your blood sugar levels can rise when you get stressed. If you have a lot of worries or feel overwhelmed, talking to a counselor or therapist could help.

Get enough sleep. Sleeping less than 7 hours a night can increase your insulin resistance. To get more rest, try not to nap after 3 p.m. and avoid alcohol and large meals before bed. 

Stop smoking. Tobacco can increase insulin resistance.

Keep in mind that insulin resistance is a complex condition that doctors don't fully understand. In some cases, your blood sugar levels may not drop back to normal levels. But you may still be able to manage them.

If left untreated, insulin resistance could lead to:

  • Liver disease
  • Increased triglycerides
  • Increased LDL ("bad") cholesterol
  • Heart disease
  • Eye issues
  • Some types of cancer
  • Alzheimer’s disease

Insulin resistance weight gain

In the short term, high blood sugar levels can cause you to gain weight. Losing those extra pounds can be a challenge because your body is using those fat cells to store extra glucose.

Insulin resistance and supplements

More research needs to be done, but supplements that contain any of the following may help control your blood sugar.

  • Cassia cinnamon
  • Ginseng
  • Magnesium

Make sure to talk to your doctor before trying any supplements, even if they're advertised as "safe" or "natural." They could still be harmful, based on your health or other medications you take.

Insulin resistance and your diet

No specific diet has been proven to to be the best for improving insulin resistance. But eating foods that are high in carbohydrates could make it worse. It's also a good idea to limit highly processed foods (foods where you don't recognize all the ingredients listed on the label) and high-fat foods. 

Instead, try to eat more:

High-fiber foods. These help manage your blood sugar because they keep you feeling full for a long time. 

Low-glycemic foods. The glycemic index (GI) ranks foods based on how quickly they raise your blood glucose. 

High-GI foods are often high in carbohydrates and sugar, but low on fiber. They quickly spike your blood sugar and insulin.

Examples of high-GI foods to limit include:

  • White bread
  • White potatoes
  • Bagels
  • Rice cakes
  • Baked goods like cake and doughnuts
  • Sweetened drinks like soda and fruit juice

Low-GI foods, on the other hand, have a small, slow impact on your blood glucose. These are foods to try to eat often. 

Some examples are:

  • Most types of fresh or frozen fruits
  • Fresh or frozen vegetables
  • Beans
  • Legumes (like peanuts or lentils)
  • Low-fat dairy products
  • Low-processed grains (like quinoa)
  • Yogurt
  • Brown rice
  • Leafy greens

Medium-GI foods like the ones below raise your blood sugar at an "in between" level. You can think of them as foods to eat sometimes, or in small amounts.

  • Whole-grain bread
  • Bananas
  • Cherries
  • Couscous
  • Corn
  • Oat breakfast cereals

Other eating plans to reduce insulin resistance

Your doctor could also suggest that you try:

The DASH (Dietary Approaches to Stop Hypertension) diet. This can help reduce insulin resistance and lower your blood pressure. It could also help you lose weight and improve your "good" cholesterol.

You'll try to eat more:

  • Whole grains
  • Fat-free or low-fat dairy products
  • Fruits
  • Vegetables
  • Poultry
  • Fish
  • Nuts

You'll try to cut back on:

  • Fatty meats
  • Full-fat dairy products
  • Tropical oils (like coconut and palm oils)
  • Sweets 
  • Sugar-sweetened drinks

The Mediterranean diet. This is a way of life rather than a meal plan. It's been shown to help with insulin resistance and can lower the risk of type 2 diabetes. You'll try to eat more healthy, fresh food that's in season instead of fast food you eat on the go or heat up at home. You'll also try to get regular exercise and think of mealtime as a time to relax and spend time with friends and family.

Generally speaking, you'll:

  • Eat fruits, vegetables, beans, whole grains, fresh herbs, spices, legumes, and seeds every day
  • Use extra-virgin olive oil
  • Often eat fermented dairy products like yogurt and cheese
  • Eat fish and seafood twice a week
  • Eat eggs and chicken sometimes
  • Rarely eat sweets, processed foods, or red meat
  • Drink lots of water

Talk to your doctor about the eating changes they feel will benefit you the most. 

Insulin resistance doesn't guarantee that you'll get diabetes. But it's important to make changes to your eating habits and activity level, since healthy daily habits can protect your health. Getting your blood checked regularly will help your doctor keep an eye on your glucose levels.