Normally - insulin is a hormone that reduces the amount of glucose in the blood
Diabetes - High glucose levels in the blood
Type 1 - autoimmune, starts in young people, there is not enough insulin being produced (by the pancreas) and therefore blood glucose levels increase
Type 2 - most common, in obesity/older people/black and asians/high blood pressure, insulin is being made but is not reacting properly with the insulin receptors which are in various tissues in the body, therefore glucose levels start to rise