A metabolic condition in which the body’s cells respond weakly to insulin, so the pancreas must produce extra insulin to keep blood glucose normal. Over time this compensation can fail, leading to elevated blood sugar, prediabetes, and type 2 diabetes. Insulin resistance is closely linked to excess abdominal fat, physical inactivity, and diets high in refined carbohydrates, and it forms a core feature of metabolic syndrome alongside raised blood pressure and abnormal blood lipids. It can be improved substantially through weight loss, regular exercise, and dietary changes that moderate glycaemic load. Clinicians assess it using fasting glucose and insulin measurements or formal glucose tolerance testing.