Insulin Resistance

Insulin is a hormone produced by the pancreatic beta cells in response to rising blood glucose — it acts as a 'key' allowing glucose to enter cells for energy. Insulin resistance occurs when cells (particularly in muscle, liver, and fat tissue) become less responsive to insulin's signal — requiring higher insulin levels to achieve the same effect. The pancreas compensates by producing more insulin (hyperinsulinaemia), maintaining near-normal glucose levels. When beta cell capacity is exhausted, blood glucose rises — producing type 2 diabetes.

Insulin resistance is the central feature of metabolic syndrome — a cluster of cardiovascular risk factors: central obesity (abdominal fat), elevated fasting glucose, high triglycerides, low HDL cholesterol, and hypertension. It is strongly associated with non-alcoholic fatty liver disease (NAFLD), polycystic ovary syndrome (PCOS), and increased cardiovascular risk. In Korea, rising rates of obesity, physical inactivity, and Westernised high-carbohydrate diets are contributing to increasing insulin resistance, particularly among younger adults.

Insulin resistance is partially reversible through lifestyle intervention: weight loss (even 5–10% body weight reduction dramatically improves insulin sensitivity), aerobic exercise and resistance training, reduced refined carbohydrate and sugar intake, and sleep optimisation (sleep deprivation worsens insulin resistance). Metformin and GLP-1 receptor agonists (semaglutide) pharmacologically improve insulin resistance. HOMA-IR (fasting insulin × fasting glucose / 22.5) is a validated assessment tool.