Diabetes is an inability to control blood sugar levels. Ordinarily, your pancreas creates a hormone called insulin in response to the amount of glucose in your blood: if there is a high level of glucose, your body churns out insulin, which tells your cells to take in the glucose and convert it into energy the cells can use. If you have diabetes, your cells fail to do so, either because you are not making enough insulin or because the insulin isn’t doing its job properly.
Type 1 diabetes develops when the insulin-producing cells in the body have been destroyed and the body is unable to produce any insulin at all. In type 2 diabetes, the most common, your organs don’t make enough.