What is insulin resistance?
Insulin resistance is a metabolic condition in which the body's cells, particularly muscle, liver and fat tissue cells, no longer respond effectively to insulin. As a result, the pancreas must produce increasing amounts of insulin to keep glucose within normal limits.
Think of insulin as a key opening a cell's door so blood glucose can enter. With insulin resistance, the cells' “locks” become stiff: the key, insulin, no longer works as well, and some glucose remains in the blood. The pancreas compensates by producing more keys, or more insulin, but over time this overwork leads to pancreatic exhaustion.
Insulin resistance is not a disease in itself, but a pathophysiological mechanism underlying several conditions: prediabetes, type 2 diabetes, metabolic syndrome, non-alcoholic fatty liver disease and polycystic ovary syndrome.
The link with prediabetes and type 2 diabetes
Insulin resistance is the first stage in a metabolic continuum:
- Stage 1 – Compensated insulin resistance: the pancreas produces more insulin and glucose remains normal, but fasting insulin is elevated (hyperinsulinism)
- Stage 2 – Prediabetes: the pancreas no longer compensates sufficiently and glucose begins to rise slightly (100–125 mg/dL fasting or HbA1c 5.7–6.4%)
- Stage 3 – Type 2 diabetes: pancreatic beta cells are significantly exhausted and glucose exceeds diagnostic thresholds (≥ 126 mg/dL fasting or HbA1c ≥ 6.5%)
The good news: insulin resistance and prediabetes are reversible in most cases through lifestyle changes. Early intervention can completely prevent type 2 diabetes developing.
How it is diagnosed: the HOMA-IR index
Insulin resistance cannot be diagnosed through a single test, but several methods are used in practice:
The HOMA-IR index (Homeostatic Model Assessment of Insulin Resistance)
This is the most commonly used indicator in clinical practice. It is calculated from simple blood tests:
HOMA-IR = (Fasting glucose [mg/dL] × Fasting insulin [μIU/mL]) / 405
Approximate interpretation:
- < 1.0 – optimal insulin sensitivity
- 1.0–2.0 – normal
- 2.0–2.9 – mild insulin resistance
- ≥ 3.0 – significant insulin resistance
It is important to know that reference values may vary slightly between laboratories. Interpretation must always be made by a doctor in the clinical context.
Other useful investigations
- Fasting insulin – high levels (above 15–20 μIU/mL) suggest insulin resistance
- Glucose profile (OGTT with insulin) – a glucose tolerance test measuring insulin at 0, 30, 60, 90 and 120 minutes; the most informative test
- Triglycerides/HDL cholesterol – a ratio > 3.0 suggests insulin resistance
- C-reactive protein (CRP) – an inflammation marker that is often elevated
Symptoms of insulin resistance
Insulin resistance develops gradually and often causes no obvious symptoms in early stages. As it progresses, the following may appear:
- Chronic fatigue, particularly after carbohydrate-rich meals – cells do not receive enough energy
- Difficulty losing weight – hyperinsulinism promotes fat storage and blocks fat burning
- Abdominal fat accumulation – increased waist circumference (>94 cm in men, >80 cm in women)
- Intense cravings for sweets and carbohydrates – glucose fluctuations generate cravings
- Hunger soon after a meal
- “Brain fog” – difficulty concentrating, especially after meals
- Acanthosis nigricans – dark, velvety skin areas on the neck, armpits or skin folds
- Skin tags (small skin growths) – often associated with insulin resistance
- Menstrual disorders in women – irregular cycles, often associated with polycystic ovary syndrome
- Slightly elevated blood pressure
If these symptoms sound familiar, an online medical consultation can help determine whether you need further investigations.
Dietary changes to reduce insulin resistance
Nutrition is the strongest tool in tackling insulin resistance. The essential principles are:
What to include in your diet
- Non-starchy vegetables – broccoli, spinach, cauliflower, peppers, tomatoes and cucumbers; these should occupy half the plate
- Lean protein – chicken, turkey, fish (especially oily fish: salmon, sardines and mackerel), eggs and tofu
- Healthy fats – extra virgin olive oil, avocado, nuts, seeds and oily fish
- Soluble fibre – oats, pulses (lentils, chickpeas and beans), chia seeds and flaxseeds
- Complex carbohydrates with a low glycaemic index – quinoa, brown rice and sweet potatoes, in moderate amounts
- Low-glycaemic-index fruit – berries, apples and pears, in moderate amounts: 1–2 portions/day
What to reduce or avoid
- Added sugar – fizzy drinks, juice, sweets and cakes
- Refined carbohydrates – white bread, white pasta, white rice and pastries
- Ultra-processed foods – processed meats, packaged snacks and ready meals
- Excess trans and saturated fats – margarine, fried food and fast food
- Excess alcohol – contributes to fatty liver and worsens insulin resistance
A personalised nutrition plan developed by a specialist can significantly accelerate progress and be adapted to your preferences and lifestyle.
The role of exercise
Physical activity is as important as nutrition in tackling insulin resistance:
- Aerobic exercise (brisk walking, running, cycling or swimming) – at least 150 minutes/week. Improves insulin sensitivity for 24–72 hours after exercise
- Resistance training (weights, resistance bands or bodyweight exercises) – 2–3 sessions/week. Muscle is the body's largest glucose “consumer”
- Reducing sedentary time – stand up and move for 5 minutes for every hour spent sitting
- Walking after meals – even 10–15 minutes after a meal can significantly reduce postprandial glucose
Studies show that regular exercise can improve insulin sensitivity by 25–50%, even without significant weight loss.
Medication options
When lifestyle changes are insufficient, the doctor may prescribe:
- Metformin – the first medicine recommended; improves insulin sensitivity and reduces liver glucose production. It can be prescribed even at the prediabetes stage
- GLP-1 agonists (semaglutide, liraglutide) – reduce appetite, improve insulin release and help weight loss. Wegovy is a popular option
- SGLT2 inhibitors – remove excess glucose through urine and help weight loss
- Pioglitazone – an insulin sensitiser used in selected cases
- Inositol (myo-inositol and D-chiro-inositol) – a supplement with evidence in polycystic ovary syndrome
Important: Do not take medicines without a prescription. Treatment must be individualised according to your metabolic profile, comorbidities and treatment goals.
Monitoring progress
If you have been diagnosed with insulin resistance, regular monitoring is essential:
- Every 3–6 months: fasting glucose, fasting insulin, HOMA-IR and HbA1c
- Every 6–12 months: a full lipid profile, liver function (ALT, AST, GGT) and abdominal ultrasound for fatty liver
- Continuously: monitor weight, waist circumference and blood pressure
Improving HOMA-IR values and a smaller waist circumference are good signs that interventions are working. Celebrate every improvement, even small ones.
Conclusion
Insulin resistance is common and often underdiagnosed, but is largely reversible through lifestyle changes. Balanced nutrition, regular activity and medication when needed can restore insulin sensitivity and prevent progression to type 2 diabetes.
Do not postpone medical assessment. The earlier you intervene, the better the results. Book an online consultation on Clinica Virtuală to discuss your metabolic profile with a specialist and receive personalised recommendations.
