Diabetes is a group of metabolic disorders defined by chronic hyperglycemia, resulting from defects in the production or action of the hormone insulin. The primary physiological dysfunction involves the inability of cells to adequately utilize circulating blood glucose, leading to elevated blood sugar levels. These conditions can arise from autoimmune processes that damage the cells responsible for insulin secretion, or from peripheral resistance, where target tissues fail to respond effectively to insulin signaling. Elevated glucose levels, if left unmanaged, can cause cumulative damage to various organ systems, including the eyes, kidneys, and nerves. Management requires systemic approaches involving dietary modifications, physical activity, and various pharmacological interventions to maintain glucose homeostasis and prevent long-term complications.