Diabetes is a disease in which blood sugar levels are above normal. People with diabetes have problems converting food to energy. After a meal, food is broken down into a sugar called glucose, which is carried by the blood to cells throughout the body.
Cells use the hormone insulin, made in the pancreas, to help them process blood glucose into energy. Insulin is secreted when glucose from a meal enters the bloodstream. The only way cells in the body are able to process glucose into energy is through insulin. Without it, the blood levels of glucose continue to rise, leading to damage of cells in the body.
People develop type 2 diabetes because the cells in the body do not use insulin properly. Eventually, the pancreas cannot make enough insulin for the body's needs. As a result, the amount of glucose in the blood increases while the cells are starved of energy. Over the years, high blood glucose damages nerves and blood vessels, leading to complications such as heart disease, stroke, blindness, kidney disease, nerve problems, gum infections, and amputation.
National Institute of Digestive and Diabetes and Kidney Diseases (NIDDK), National Institutes of Health (NIH).