If you're not opposed to eschewing professional recommendations to not complicate treatment, there are two things that may be worth looking into:
1). Metformin: Helps control blood glucose by significantly increasing sensitivity of insulin receptors, i.e more glucose is shuttled out of the blood stream per insulin molecule. Not scheduled and very cheap. Also trials are being done on it for cancer prevention -- exactly because of Warburg's phenomenon (cancer cells and glucose)
2). Ketosis: Hit or miss. By abstaining from carbohydrate consumption, the result should be drastically reduced blood glucose levels. However, in some people (e.g type 2 diabetics) it may elevate blood glucose due to metabolic disfunction. In any case, caloric restriction in general have the effect of both increasing insulin sensitivity and decreasing blood glucose -- regardless of macronutrient profile