Diabetes mellitus is the medical name given to the disease in which the amount of glucose in the bloodstream is too high as the body is unable to regulate blood glucose levels properly. Glucose comes from digesting carbohydrates from food and drinks we consume and is also produced in the liver. Carbohydrates come from lots of different foods and drinks such as starchy foods including bread, potatoes, pasta, rice as well as fruit, sugar and other sweet things such as fizzy drinks etc.
Insulin is a hormone produced by the pancreas and it helps the glucose in your blood to enter the cells where it is used to for energy to power our cells and muscles. Diabetes is the body's inability to control the level of glucose in the blood due to inadequate insulin being produced in the pancreas.