What Is Insulin Resistance? Symptoms, Causes & Prevention
When most people think about blood sugar, they think about diabetes. But changes in how your body responds to insulin can begin long before you’re diagnosed with prediabetes or type 2 diabetes.
One of the things I emphasize with my patients is that we shouldn’t wait until someone develops diabetes to start talking about their metabolic health.
Understanding insulin resistance is an important part of that conversation.
What Is Insulin Resistance?
Insulin is a hormone produced by your pancreas that helps move glucose (sugar) from your bloodstream into your body’s cells, where it can be used for energy.
Think of insulin as a key that helps glucose enter your cells.
When you develop insulin resistance, your body’s cells don’t respond to insulin as effectively as they should. Your pancreas compensates by producing more insulin to help keep your blood sugar within a normal range.
For a while, this can work. You may have insulin resistance while your blood sugar levels remain normal.
Over time, however, your pancreas may no longer be able to produce enough insulin to overcome that resistance. Blood sugar levels can begin to rise, potentially leading to prediabetes or type 2 diabetes.
The important point is that insulin resistance can develop before your blood sugar becomes abnormal.
What Causes Insulin Resistance?
Insulin resistance develops through a combination of factors. These may include:
Excess body fat, particularly around the abdomen
Physical inactivity
Family history and genetic predisposition
Inadequate sleep
Certain medications and medical conditions
Insulin resistance is also associated with conditions such as polycystic ovary syndrome (PCOS), fatty liver disease, high blood pressure, and abnormal cholesterol levels.
Not everyone who develops insulin resistance is overweight, and not everyone who is overweight has insulin resistance.
That’s why evaluating metabolic health requires looking at more than someone’s weight.
What Are the Symptoms of Insulin Resistance?
Here’s something that surprises many people: insulin resistance often doesn’t cause noticeable symptoms.
You may feel perfectly fine while changes are occurring in how your body processes glucose.
Some people with insulin resistance may also have increased abdominal fat, elevated blood pressure, abnormal cholesterol levels, or darkened, velvety skin around the neck or underarms, known as acanthosis nigricans.
However, symptoms such as fatigue, cravings, or difficulty losing weight are not specific enough to diagnose insulin resistance.
This is one reason appropriate preventive screening and understanding your lab results are so important.
Can You Have Insulin Resistance With Normal Blood Sugar?
Yes.
Early in the development of insulin resistance, your pancreas may produce enough additional insulin to maintain normal blood glucose levels.
But there’s another important distinction I want patients to understand: a normal fasting blood glucose does not always mean your A1c is normal.
These tests measure different things.
A fasting blood glucose measures the amount of glucose in your blood at a specific point in time, after fasting.
Hemoglobin A1c (HbA1c) reflects your average blood glucose over approximately the previous two to three months.
In my practice, I sometimes see patients whose fasting glucose is within the normal range, but whose A1c is in the prediabetes range.
If we only look at fasting glucose, we may miss information that another appropriate screening test could provide.
Know Your Numbers
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| Fasting glucose | Below 100 mg/dL | 100–125 mg/dL | 126 mg/dL or higher |
| Hemoglobin A1c | Below 5.7% | 5.7–6.4% | 6.5% or higher |
These are standard diagnostic ranges for nonpregnant adults. A diagnosis of diabetes generally requires confirmation unless there is unequivocal hyperglycemia.
It’s also important to understand that A1c does not directly measure insulin resistance, and it isn’t the appropriate test for every patient. Certain medical conditions can affect A1c accuracy.
The decision about which screening tests to order should be based on your age, risk factors, medical history, and clinical circumstances.
Can Insulin Resistance Be Improved?
Yes. Insulin sensitivity can often improve with changes in physical activity, nutrition, sleep, and weight management when appropriate.
You don’t have to change everything overnight.
Here are three practical places to start.
Move Your Body After Meals
Taking a 10–15 minute walk after eating can help your muscles use glucose for energy and reduce the rise in blood sugar after a meal.
You don’t have to go to the gym to benefit from movement.Prioritize Protein and Fiber
Build meals around foods that provide protein and fiber, including lean proteins, beans, vegetables, whole grains, nuts, and seeds.
Fiber helps slow carbohydrate absorption, while protein-containing foods can help with fullness and support muscle maintenance.
You don’t necessarily have to eliminate carbohydrates. The types of carbohydrates you choose, your portions, and what you eat with them all matter.
Include Strength Training
Muscle tissue plays an important role in glucose metabolism.
Strength training helps maintain or increase muscle mass and can improve insulin sensitivity over time.
Activities such as resistance bands, body-weight exercises, and lifting weights can all be beneficial.
Adequate sleep and managing other health conditions are also important parts of metabolic health.
Do You Need Medication for Insulin Resistance?
Not everyone does.
Lifestyle changes are foundational, but some patients may benefit from medication depending on their overall metabolic health, weight, diabetes risk, and other medical conditions.
For certain people at higher risk of developing type 2 diabetes, metformin may be considered. Weight-management medications may also be appropriate for eligible patients, but they are not automatically indicated simply because someone has insulin resistance.
Treatment should be individualized rather than based on a single number.
The Bottom Line: Don't Wait for Diabetes to Think About Your Metabolic Health
Your metabolic health is about more than whether you’ve been diagnosed with diabetes.
Blood sugar, blood pressure, cholesterol, physical activity, sleep, and body composition all contribute to the bigger picture.
And while insulin resistance can be an early part of the progression toward type 2 diabetes, it does not mean that diabetes is inevitable.
Small, consistent changes can make a meaningful difference.
At LIGHT Family Wellness, my goal is to help patients understand their health, recognize opportunities for prevention, and develop realistic plans that support their long-term well-being.
You deserve to understand your numbers and what they mean for your health.
Frequently Asked Questions
Is insulin resistance the same as prediabetes?
No. Insulin resistance refers to how the body’s cells respond to insulin. Prediabetes means blood glucose levels are above normal but below the threshold for diabetes. They often occur together, but they are not the same condition.
Can you have insulin resistance without being overweight?
Yes. Genetics, physical activity, body fat distribution, certain medical conditions, and other factors can contribute to insulin resistance at any body weight.
Does a normal A1c mean I don't have insulin resistance?
Not necessarily. A1c measures average glucose, not insulin sensitivity. Insulin resistance may be present while A1c remains normal.
Should everyone have their insulin level checked?
No. Routine fasting insulin testing is not generally recommended for diagnosing insulin resistance in everyday clinical practice. Your clinician can assess metabolic risk using your history, examination, and appropriate laboratory testing.
Can insulin resistance be reversed?
Insulin sensitivity can improve significantly with lifestyle changes and, when appropriate, medical treatment. The degree of improvement varies from person to person.
