Type 1 diabetes is often diagnosed in childhood (although some people can be diagnosed later in life). It is classed as an auto-immune problem because the person’s own immune system kills the cells (beta-cells) in the pancreas that produce insulin.
This means that a type 1 diabetic needs to have insulin injections (or an insulin pump) for the rest of his or her life in order to survive.
Type 2 diabetes is often called middle-aged onset diabetes, because it develops later in life and is often associated with being overweight. In type 2 diabetes, the pancreas does produce insulin but the body stops responding to it and the person becomes insulin resistant. So the pancreas will try to produce more insulin to overcome this resistance. The first line of treatment in type 2 diabetes is insulin sensitising medication. But if the pancreas keeps having to overwork then the beta cells in the pancreas may fail and insulin injections or a pump will be required.
Having too much sugar in your diet can cause you to become insulin resistant. Your insulin receptors do not open in response to insulin and the glucose from your blood is not moved into your cells. This means you are not getting the energy you need from your food and also that you end up with high blood glucose (sugar).