Type 2 diabetic patients pass through a phase of impaired glucose tolerence and/or impaired fasting glucose known as 'prediabetic state'. Prediabetic state form a part of syndrome X, other components being obesity, hypertension, dyslipidaemia, hyperinsulinaemia and insulin resistance. The pathophysiology of prediabetes is similar to type 2 diabetes mellitus, two basic defects are insulin resistance and early beta cell failure. In prediabetes, the rapid oscillations of insulin secretion are lost and amplitude of large pulses are decreased. When insulin is delivered in a pulsatile fashion that mimics the normal rapid oscillation, its hypoglycaemic effects are greater. In prediabetes, the glycaemic excursions after each meal are high and early insulin responses to meals tend to be lower than normal but the second phase of insulin secretion is delayed and prolonged.