What is Insulin Resistance - How Do I Know if I Have It?

By Prof. Nelly Pitteloud

Before blood sugar rises, insulin does.

Long before a person is diagnosed with type 2 diabetes, cardiovascular disease, or even cognitive decline, a silent metabolic shift often begins: insulin levels start creeping upward. Chronically elevated insulin—also called hyperinsulinemia—is an early sign that your metabolism is struggling, often years before standard blood glucose tests show anything abnormal. High insulin levels often signal that the body is becoming insulin resistant—that is, cells no longer respond effectively to insulin’s message.

The good news? You can act early.

Insulin: A Crucial Hormone in Glucose Regulation

Produced by the beta cells in the pancreas, insulin is the body’s main anabolic hormone—it helps build and maintain structures throughout the body: muscle, bone, fat, and glycogen stores.

Its most visible role is to shuttle glucose from the bloodstream into cells, where it’s used for energy or stored for later use, maintaining blood sugar balance. It does so by binding to receptors on cell surfaces, which triggers the movement of special glucose transporters (such as GLUT4) to the cell membrane.

Yet the influence of insulin extends far beyond blood sugar:

• In muscle, insulin helps store glucose and stimulates protein synthesis.

• In the liver, it promotes glucose storage (glycogen) and regulates glucose release during fasting.

• In the brain, insulin affects memory, appetite regulation, and cognition.

• In bones, it supports bone formation and mineralization.

• In the kidneys, it alters sodium retention, impacting fluid balance and blood pressure.

• In fat tissue, it drives fat storage—especially when glucose is in excess.

  
  

Insulin is essential. But when levels are chronically high, problems begin.

When Insulin Goes Wrong: The Risk of Hyperinsulinemia

High insulin levels often signal that the body is becoming insulin resistant—that is, cells no longer respond effectively to insulin’s message. To compensate, the pancreas secretes even more insulin, trying to keep blood glucose levels in check.

This metabolic tug-of-war can go on for years silently. But over time, the consequences become visible:

• Increased abdominal fat

• Higher triglycerides and risk of fatty liver

• Elevated blood pressure

• Progression to prediabetes and type 2 diabetes

• Increased risk for cardiovascular disease and cognitive decline

• Worsening of polycystic ovarian syndrome

  
  

What’s a Healthy Insulin Level ?

Fasting insulin can be measured with a simple blood test after an overnight fast. An optimal fasting insulin range is below 10 μU/mL—ideally around 2–6 μU/mL. Lower fasting insulin levels are a marker of high insulin sensitivity, which is what you want: the body needs less insulin to do its job.

Tests like fasting glucose and insulin levels, HOMA-IR, and continuous glucose monitoring (CGM) response patterns can provide early clues. HOMA-IR is calculated from fasting insulin and glucose. CGMs can reveal exaggerated or prolonged blood sugar spikes after meals.

Why High Insulin Is Dangerous ?

Excess insulin drives fat storage—especially visceral fat. It also:

• Impairs fat burning

• Promotes inflammation

• Elevates triglycerides and blood pressure

• Worsens hormonal imbalances

• Fuels liver fat accumulation

• Disrupts cognitive function and appetite regulation

  
  

Eventually, the body’s insulin-producing beta cells may “burn out,” leading to rising blood glucose—and full-blown diabetes. But the dysfunction starts much earlier.

Early Signs to Watch For:

• Persistent fatigue

• Belly fat gain

• Hunger after meals

• Increased thirst

• Irregular periods

• Dark skin patches

What You Can Do: Proven Ways to Lower Insulin

1. Cut Back on Refined Carbs and Added Sugars

• Refined grains, sugary drinks, and packaged snacks cause sharp spikes in blood glucose and insulin.

• Reducing these foods lowers insulin demand and allows your body to regain insulin sensitivity.

• Focus on whole, unprocessed foods: vegetables, legumes, whole grains, nuts, seeds, healthy fats, and lean proteins.

  
  

2. Practice Intermittent Fasting

• Time-restricted eating (such as eating within an 8–10 hour window) can help lower fasting insulin and improve metabolic flexibility in some individuals but not all.

• Periods of fasting give your body a chance to lower insulin and use stored energy more efficiently.

  
  

3. Move Regularly

• Both aerobic exercise (walking, cycling, swimming) and resistance training (weights, bodyweight exercises, yoga) improve insulin sensitivity.

• Exercise helps build muscles which in turn improve glucose uptake and insulin sensitivity.

• Aim for at least 150 minutes of moderate-intensity exercise per week, plus 2–3 sessions of resistance training, and move every day.

  
  

4. Increase Fiber and Antioxidants

• Fiber slows glucose absorption, helping blunt post-meal insulin spikes.

• A diet rich in vegetables, fruits, whole grains, legumes, and nuts provides fiber and antioxidants.

• AntioxidantsH help reduce inflammation and oxidative stress, both of which contribute to insulin resistance.

  
  

5. Prioritize Sleep and Manage Stress

• Poor sleep and chronic stress elevate cortisol, a hormone that worsens insulin resistance.

• Aim for 7–9 hours of quality sleep per night.

• Incorporate stress-reducing practices such as yoga, mindfulness, meditation, nature walks, or deep breathing.

📌 THE FACTS

• Hyperinsulinemia/Insulin resistance can be silent for years.

• You don’t need to be overweight to have it.

• Common in people with belly fat, PCOS, or lipid issues.

• Simple blood tests can help detect it early.

WHY IT MATTERS

Insulin resistance is about more than blood sugar. It affects energy, inflammation, hormones, and long-term disease risk. Caught early, it’s reversible. Left unaddressed, it can progress to diabetes, infertility, heart and liver disease. Refer to the list of signs above and do not hesitate to be tested.