Diabetes is a defect in the body’s ability to convert glucose to energy. Most of the food people eat is broken down into glucose, the form of sugar in the blood. Glucose is the main source of fuel for our body. Normally, blood glucose levels are tightly controlled by insulin, a hormone produced by the pancreas, a large gland behind the stomach. 

When people eat, the pancreas automatically produces the right amount of insulin to move glucose from blood into the cells. In patients with diabetes, the pancreas either produces little or no insulin, or the cells do not respond appropriately to the insulin that is produced, which results in hyperglycemia. 

Glucose builds up in the blood, overflows into the urine, and passes out of the body in the urine. Thus, the body loses its main source of fuel even though the blood contains large amounts of glucose. Diabetes is a chronic medical condition, meaning that although it can be controlled, it lasts a lifetime.