Basically (and very simply put) Type 1 (sometimes called Juvenile Onset diabetes) is when your body's pancreas stops or almost totally stops producing insulin. This can be caused by viral infections, an auto-immune disorder and several other things. With Type 1 you have to start on insulin to get glucose into your cells or your body will starve to death because the insulin acts as a glucose transporter. The glucose (blood sugar) is there in the blood stream but unable to get through the cell walls into the cells.
Type 2 is when your body becomes resistant to it's own insulin and you have a difficult time moving the glucose into your cells. The body's metabolism is goofed up enough that it will convert glucose into fat and store it instead of passing it into the cells. So the whole time the cells in your body are sending "I'm HUNGRY!" signals to your brain and there's tons of glucose floating around in your blood stream.
Different things will help your blood sugar be moved into the cells where you can utilize it for energy. Exercise helps your body use available insulin more efficiently. Medications work in a variety of ways to help your body utilize glucose or improve the way your own insulin works. Some herbs and minerals will affect blood sugar and help your body do its job. Some diet plans will lower the amount of carbs (which turn into sugar in your body) available and make your body use up excess fat. There are a lot of different ways to approach this disease and a variety of opinions on what works best in conjunction with what. Basically exercise, good nutrition, rest and frequent blood sugar checks along with whatever meds your doc has prescribed is the middle of the road course of action that most diabetics follow.
Pre-diabetes is usually when you have slightly elevated blood sugar indicating the need for more exercise or a tighter watch on your diet. Some studies have shown that prolonged intake of corn syrup and hydrogenated fats in foods have increased the tendency to become pre-diabetic. If that is one of the causes of diabetes then your age may make you a candidate for changing your diet to more fresh fruits and veggies, and less refined starch products. Because arteriosclerosis and heart attacks are linked to diabetes doctors are being more agressive in their battle against high blood sugar.
I have given you a bare bones description of most of this and there are others here who are much better educated than I on the subject but I hope this helps you out.
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