What is insulin resistance?

Amy Brownstein, MS, RDN - Registered Dietitian Nutritionist

It's popping up everywhere–the phrase, insulin resistance–but what is it, and how does it impact your health? Although insulin resistance can negatively affect your health, the good news is that it is often reversible with lifestyle changes such as regular exercise, portion control, and weight management.

What is insulin resistance?

Insulin resistance is when your body’s cells don’t respond properly to insulin, the hormone secreted by the pancreas when blood sugar levels rise. Insulin acts like a key to unlock cells in your muscles, liver, and fat, letting blood sugar (glucose) in, thus lowering blood sugar levels in your circulation.

When you have insulin resistance, your cells don’t respond to normal amounts of insulin, causing more glucose to remain in your bloodstream. Initially, the pancreas compensates by producing more insulin, leading to elevated insulin levels (hyperinsulinemia) even when blood sugar remains normal. Over time, this cycle contributes to high blood sugar levels and increases the risk of developing metabolic diseases, such as fatty liver disease, type 2 diabetes, and heart disease.

How does insulin resistance occur?

Multiple factors contribute to the development of insulin resistance. Consuming excess calories, excess body fat, and inflammation all disrupt insulin activity, contributing to insulin resistance.

What are risk factors for insulin resistance?

Some individuals are at a greater risk of developing insulin resistance. Risk factors for insulin resistance include:

Genetics and family history
Being overweight or obese
A larger waist circumference
Age
Race and ethnicity
Physical inactivity
Smoking
History of gestational diabetes
Polycystic ovary syndrome
Frequent use of certain medications, such as steroids

You can’t change some of these risk factors, but others can be modified with dietary and lifestyle changes.

Is insulin resistance the same as type 2 diabetes?

No, insulin resistance is not the same as type 2 diabetes. However, insulin resistance is a key feature and a major risk factor of type 2 diabetes.

Insulin resistance is when your body does not respond properly to the hormone insulin. Type 2 diabetes is a combination of the body not responding to insulin plus inadequate insulin production from the pancreas, leading to persistent high blood sugar.

Does insulin resistance cause type 2 diabetes?

Left untreated, insulin resistance can lead to type 2 diabetes. In fact, many people may have insulin resistance for years without a type 2 diabetes diagnosis.

Insulin resistance causes type 2 diabetes when the pancreas is no longer able to produce enough insulin to compensate for the reduced responsiveness of muscle, liver, and fat cells.

Just because you have insulin resistance does not mean you’ll have type 2 diabetes. Insulin resistance is often an early, reversible condition that otherwise increases the risk of type 2 diabetes.

Does insulin resistance make it harder to lose weight?

Yes, insulin resistance can make weight loss more challenging.

Even though insulin is necessary, it also prevents fat breakdown and encourages fat storage. Additionally, elevated insulin levels make it harder for the body to break down and use fat for energy, leading it to rely more on other sources of energy. Combined, these factors make it more difficult to lose weight in the presence of insulin resistance.

Still, weight loss is possible even with insulin resistance. Adhering to a calorie deficit can lead to changes in body composition and weight loss, both of which reduce insulin resistance.

How to improve insulin resistance

Now that you know more about what insulin resistance is and what it isn't, consider these healthy ways to reverse insulin resistance, which are also ideal practices for improving overall health.

Get active. Aim for 150 minutes of moderate-intensity aerobic exercise plus two sessions of strength training each week.
Replace refined carbohydrates with whole grains. Swap regular bread, pasta, baked goods, or desserts for whole-grain varieties like quinoa, whole-wheat bread, farro, brown rice, or whole-wheat pasta. Whole grains contain more fiber, which helps slow the absorption of sugar in your bloodstream, leading to more stable glucose levels.
Reduce your fat intake. Consuming too much fat—particularly saturated fat from animal foods, full-fat dairy, and packaged goods—contributes calories and may alter body composition, potentially affecting insulin signaling. Use MyNetDiary to set custom intakes for fat to help you manage insulin resistance.
Quit smoking. Smoking increases your risk of developing insulin resistance.
Prioritize routine blood work. Checking glucose and hemoglobin A1C levels yearly allows you to monitor trends in insulin and blood sugar levels, so you can make changes early.