Sarah,
T1 and T2 are two related but very different conditions. So there can be no switching between them. But a newly afflicted T1 will often present with T2 symptoms. During this "honeymoon" period, the pancreas still procduces some insulin. So blood sugar can be controlled by diet, exercise and medications that increase the pancreas' output of insulin. Which is how T2s can usually be controlled. But this situation doesn't last. Eventually, the pancreas gives up the ghost and the honeymoon comes to an end. The now fully-fledged T1 diabetic becomes completely dependent on injected insulin.
The transition from what initially may appear to be T2 to being an insulin dependent T1 is a one-way street. Once the pancreas closes down completely, there is no way to restore it's insulin manufacturing ability. And there is no going back ... Or not at the moment anyway.
A good site for basic information about diabetes is the
diabetes section of the Howstuffworks website. It is written for the layman, there are some good illustrations, and on the last page there are lots of links to other useful sites.
Cheers,
Mark
