Type 2 Diabetes: Role of Diet and Nutrition - Hardcoverby Vanessa Artiga (Editor) Diabetes refers to a group of metabolic disorders that are characterized by having high blood sugar level over a long time. Type 2 diabetes (T2D) is a type of diabetes which is characterized by relative lack of insulin, high blood sugar and insulin resistance. The usual symptoms of T2D are frequent urination, unexplained weight loss and increased thirst. There can be other symptoms such as fatigue, increased hunger and sores