This document defines diabetes and describes its main types. It discusses that diabetes is a metabolic disease where the body does not produce any or enough insulin, causing high blood sugar. The main types of diabetes are type 1, type 2, and gestational diabetes. Type 1 is characterized by the immune system destroying insulin-producing cells and the body not producing insulin. Type 2 is the most common type where the body produces insulin but does not use it properly. Gestational diabetes occurs during pregnancy. Risk factors, symptoms, complications, treatment, and nursing care plans are also summarized.