Diabetes is a metabolic disorder that results in elevated levels of blood glucose due to either pancreatic inability to produce insulin (type 1 diabetes) or cells’ inability to effectively respond to circulating insulin (insulin resistance) (Diabetes UK, 2004). There are four diabetic categories. Type 1 diabetes is characterised by complete lack of insulin production and therefore regular supply of insulin is needed. Type 2 diabetes is mainly characterised by insulin resistance which may develop into insufficient insulin production. Common treatment approach involves administration of oral hypoglycaemic agents or insulin sensitising antihyperglycaemic agents. About 35-40% of patients with long-term type 2 diabetes may also require exogenous insulin administration. Gestational diabetes may develop during pregnancy but usually elevated levels of glucose return to normal after delivery. The fourth category is termed ‘other specific types’ which are strongly related to certain diseases or genetic predispositions (American Diabetes Association, 2004a). The general criteria for diagnosing diabetes are presented in Table 16.1.