Diabetes is a disease that occurs when the blood sugar (also called blood glucose) is too high. Blood glucose is the main source of energy and comes from the food a person eats.
Insulin, a hormone which is build in the pancreas, is necessary to get glucose from food into the cells to be used for energy. When having a diabetes the body doesn’t make enough — or any — insulin or doesn’t use insulin well. The result is that Glucose then stays in the blood and can’t reach the cells.