If you have Type Two diabetes, you probably can (or could have) reduced almost all the problems by radically reducing your weight and exercise. None of the books from either reputable or not so repspectable sources say otherwise. Even someone who sits and learns, can easily control his diet by eating less and such simple exercise as walking routinely. There are no halachic issues to the contrary, and our gedolim tend to be thin and frequently walk rather than ride (especially the long-lived ones).
If you have Type One diabetes you are either taking insulin shots or you are dead (before artificial insulin was invented, type one diabetes was inevitably fatal).