Insulin resistance means that parts of the body do not respond to insulin as effectively as they should.
This article is part of the AKK Knowledge Centre, our guide hub for metabolic wellness, gut health and Akkermansia research.
For related context, see what metabolic health means.
Insulin is a hormone produced by the pancreas.
Its job includes helping regulate how glucose moves between the blood and tissues such as:
- skeletal muscle,
- liver,
- and fat.
When these tissues become less responsive to insulin, the pancreas may initially compensate by producing more insulin.
For a period of time, blood glucose may remain within a normal range.
This is one reason insulin resistance can exist before a person has obvious symptoms or abnormal routine glucose results.
Key Takeaways
- Insulin helps regulate blood glucose and energy storage.
- Insulin resistance means tissues respond less effectively to insulin.
- The pancreas may compensate by producing more insulin.
- Blood glucose can remain normal early in the process.
- Insulin resistance is associated with abdominal obesity, physical inactivity, genetics, age and several medical conditions.
- Prediabetes and insulin resistance are related but not identical.
- Routine clinical practice does not always directly test “insulin resistance.”
- Lifestyle changes can improve insulin sensitivity in many people.
What Does Insulin Normally Do?
After a carbohydrate-containing meal, digestion releases glucose into the bloodstream.
The pancreas senses rising glucose and releases insulin.
Insulin signals tissues to respond.
In Skeletal Muscle
Insulin helps muscle take up glucose.
Muscle can use glucose for energy or store it as glycogen.
In the Liver
Insulin helps regulate glucose production and storage.
In Fat Tissue
Insulin influences the storage and release of fatty acids.
These systems work together to keep circulating glucose within an appropriate range.
What Changes During Insulin Resistance?
When tissues are less responsive to insulin, the body needs a stronger insulin signal to produce the same effect.
The pancreas may respond by secreting more insulin.
This compensation can maintain relatively normal glucose for some time.
But if insulin resistance progresses and pancreatic compensation becomes insufficient, blood glucose may rise.
Is Insulin Resistance the Same as Prediabetes?
No.
Insulin resistance describes reduced biological responsiveness to insulin.
Prediabetes is defined clinically by glucose measurements that are above normal but below the diagnostic range for diabetes.
A person may have insulin resistance without meeting prediabetes criteria.
Likewise, abnormal glucose regulation can involve several mechanisms.
Is Insulin Resistance the Same as Diabetes?
No.
Type 2 diabetes develops when blood glucose becomes persistently high because insulin action and insulin production are no longer sufficient to maintain normal glucose regulation.
Insulin resistance is an important part of type 2 diabetes for many people, but the terms are not interchangeable.
What Causes Insulin Resistance?
There is no single cause.
Factors associated with insulin resistance include:
- genetic predisposition,
- abdominal adiposity,
- physical inactivity,
- ageing,
- sleep disruption,
- certain medications,
- polycystic ovary syndrome,
- metabolic dysfunction-associated steatotic liver disease,
- and other medical conditions.
NIDDK notes that researchers still do not fully understand every mechanism involved.
Why Does Abdominal Fat Matter?
Visceral fat is metabolically active.
Higher abdominal adiposity is associated with:
- altered fatty-acid delivery,
- inflammatory signalling,
- changes in liver metabolism,
- and insulin resistance.
This is one reason waist circumference can be a useful risk marker.
For Asian populations, lower waist thresholds are commonly used because cardiometabolic risk can occur at lower BMI and waist values than in some Western populations.
Does Insulin Resistance Have Symptoms?
Often, no.
NIDDK notes that people with insulin resistance and prediabetes usually have no obvious symptoms.
This is why risk assessment and screening matter.
Some people may have related signs such as acanthosis nigricans, but many people have none.
How Is Insulin Resistance Diagnosed?
This is more complicated than many wellness websites suggest.
The gold-standard research method is the hyperinsulinaemic-euglycaemic clamp.
But it is complex and not routinely used in everyday clinical practice.
Clinicians more commonly assess downstream markers and risk factors using:
- fasting glucose,
- HbA1c,
- oral glucose tolerance testing,
- waist circumference,
- blood lipids,
- blood pressure,
- medical history.
Some calculations such as HOMA-IR are used in research and selected clinical contexts, but they are not a universal standalone diagnostic test.
What Is HOMA-IR?
HOMA-IR estimates insulin resistance from fasting glucose and insulin.
It can be useful in research.
But thresholds vary across populations and laboratories.
Consumers should be cautious about interpreting one online HOMA-IR calculator without clinical context.
Can Insulin Resistance Be Improved?
Yes, in many people.
Strategies that can improve insulin sensitivity include:
- physical activity,
- resistance training,
- aerobic exercise,
- weight reduction when appropriate,
- improved diet quality,
- adequate sleep,
- stopping smoking,
- and medical treatment when indicated.
The amount of improvement varies.
Why Is Exercise So Effective?
Skeletal muscle is a major site of glucose disposal.
During and after exercise, muscle can increase glucose uptake through mechanisms that are partly independent of insulin.
Regular training also improves:
- mitochondrial function,
- muscle mass,
- fitness,
- insulin signalling.
This makes physical activity one of the most powerful lifestyle tools for metabolic health.
Does Losing Weight Improve Insulin Sensitivity?
For people with overweight or obesity, weight loss often improves insulin sensitivity.
The Diabetes Prevention Program showed that relatively modest weight loss combined with physical activity substantially reduced progression to type 2 diabetes in people at high risk.
However, insulin sensitivity can improve through exercise even when weight loss is modest.
Can Sleep Affect Insulin Sensitivity?
Yes.
Controlled sleep-restriction studies in humans have shown reductions in insulin sensitivity.
A 2024 randomised crossover study in women found that chronic mild sleep restriction impaired insulin sensitivity even without changes in adiposity.
However, simply extending sleep does not guarantee an immediate improvement in insulin sensitivity for every person.
A 2026 trial in adults with overweight or obesity and habitual short sleep improved sleep duration but did not improve insulin sensitivity over approximately six weeks.
This shows why sleep science should be interpreted carefully.
Does Diet Matter?
Yes.
Diet affects:
- total energy intake,
- body weight,
- post-meal glucose,
- liver fat,
- blood lipids,
- and the gut microbiome.
No single macronutrient ratio is universally ideal.
Long-term adherence and overall dietary quality matter.
Does Eating Carbohydrate Cause Insulin Resistance?
Not by itself.
Carbohydrates include very different foods:
- lentils,
- oats,
- fruit,
- whole grains,
- sugar-sweetened drinks,
- refined desserts.
The metabolic effect of a diet depends on:
- food quality,
- total energy intake,
- fibre,
- processing,
- portion size,
- physical activity,
- and individual physiology.
The claim that “carbohydrates cause insulin resistance” is too simplistic.
Can You Feel Your Insulin Level?
No.
Feeling tired or hungry after a meal does not directly measure insulin resistance.
Symptoms alone cannot diagnose insulin resistance.
Frequently Asked Questions
What is insulin resistance in simple terms?
It means the body needs a stronger insulin signal to manage glucose and energy in tissues.
Can insulin resistance happen with normal blood sugar?
Yes, especially earlier in the process when the pancreas compensates with more insulin.
Is insulin resistance reversible?
Insulin sensitivity can improve substantially in many people through lifestyle changes and appropriate medical treatment.
Is insulin resistance caused by sugar?
No single food causes insulin resistance by itself. Overall energy balance, fat distribution, physical activity, genetics and diet quality all matter.
Do I need an insulin test?
Not necessarily. Clinicians commonly assess glucose, HbA1c and other cardiometabolic risk factors rather than directly diagnosing insulin resistance from fasting insulin alone.
The Bottom Line
Insulin resistance is not simply “too much sugar in the blood.”
It is a change in how tissues respond to a key metabolic hormone.
Because the body can compensate for a long time, insulin resistance may be present before routine glucose measurements become clearly abnormal.
The strongest long-term strategies are sustainable:
- physical activity,
- appropriate weight management,
- nutritious eating,
- adequate sleep,
- and clinical monitoring when risk is elevated.
Continue Learning
Selected Scientific References
- National Institute of Diabetes and Digestive and Kidney Diseases. Insulin Resistance & Prediabetes.
- American Diabetes Association. Standards of Care in Diabetes—2026.
- Zuraikat FM, et al. Chronic Insufficient Sleep in Women Impairs Insulin Sensitivity Independent of Adiposity Changes. Diabetes Care. 2024.
- Beals JW, Smith GI, Farabi SS, Patterson BW, Lucey BP, Broussard JL, Wright KP Jr, Klein S. Sleep Extension Improves Sleep Health but Not Insulin Sensitivity in People With Overweight or Obesity Who Maintain Habitual Short Sleep Schedules. Diabetes Care. 2026;49(5):740-745.
Educational Disclaimer
This article is for general education only. Insulin resistance, prediabetes and diabetes require appropriate clinical assessment.