Hey brightstation!
That is actually a very sensible question!
In my view, it is very important to know the underlying cause as it does matter to how I would choose to manage my diabetes. I guess you'll not be surprised to know the NHS disagrees!
Take the first scenario, Insulin Resistance: The body produces enough insulin but cannot use it properly, so the blood glucose rises and the body produces more insulin to try to bring it down but the blood glucose still rises so the body produces more insulin and on it goes. Therefore, not only will you have high blood glucose, but also high levels of insulin swimming about your blood. In this circumstance, you really wouldn't want to 'help' the body to produce more insulin or inject extra insulin - you need to help the body to use the insulin it is already producing. If you know this is what you are suffering from, you could cut the carbs to reduce the amount your struggling pancreas has to cope with, exercise to increase the ability of your body to use the insulin you produce properly and lose any excess weight you are carrying. This can be a very effective strategy to normalise blood glucose and insulin levels in a Type 2 who has insulin resistance, but strong pancreas function.
The second scenario, insufficient insulin production, is a very different kettle of fish: The body does not produce enough insulin, so the blood glucose starts to rise. Although you can do all of the above and it will probably help a bit, it won't necessarily be enough because you do not have enough insulin to keep the BG under control. You will therefore probably need an insulin-stimulating drug such as Gliclazide (there are pros and cons to this, but I won't go into that here) or insulin therapy i.e. injected insulin. There is little point in taking drugs to help the uptake of insulin (e.g. metformin) if there is insufficient insulin being produced. In Type 2, lack of insulin production is usually a problem when the BGs have been high so long before diagnosis that the pancreatic beta cells have been damaged.
In reality, most Type 2s at diagnosis have a combination of the two scenarios. They have some degree of insulin resistance that has caused the BGs to rise to a level that has damaged the pancreas and its ability to produce sufficient insulin is compromised. It depends where on this scale you are as to what is likely to be the most effective treatment. In the absence of real knowledge as to where you are on the scale, it is usually prudent to follow the strategy in scenario 1 while testing your BG before and 2 hours after meals to see how your body is reacting to the reduction in carbs and to different food. In this way, you can find a level of carb that works for you - and take an appropriate medication to help if necessary.
There is a test you can have to see how much insulin you are producing - the c-peptide test, but the NHS very rarely performs this unless they suspect you might have a form of Type 1 diabetes and are trying to differentiate this from a Type 2 diagnosis. They see the test as too expensive and believe that treatment wouldn't be any different regardless, so they believe it is pointless to find out.
Take care,
Smidge
