I would like you to fill in more symptoms of the Sugar problem.
As far as I remember, both Iodine and magnesium deficiency have their say in glucose metabolism.
In your case it may be the metabolsim OR simply that your digestion doesnt work properly.
Hows your PUFA /fat intake?
Here is an input from Ray Peat; controversial; and I dont agree with all his sayings, but I find it refreshing and have found some truth in his articles. Dont know if related to your situation; but others may benefit;
"“In Houssay’s experiments, sugar, protein, and coconut oil protected mice against developing diabetes. The saturated fats of coconut oil are similar to those we synthesize ourselves from sugar. Saturated fats, and the polyunsaturated fats synthesized by plants, have very different effects on many important physiological processes. In every case I know about, the vegetable polyunsaturated fats have harmful effects on our physiology.”"This translates to resting up and eating a high-carb, high-calorie, low-PUFA diet with a little added fat and protein and frequent feedings. It’s amazing what something so simple can do for glucose metabolism and subsequent health improvements that stem from an impairment in glucose metabolism."
“Sugar and thyroid hormone (T3, triiodothyronine) correct many parts of the problem. The conversion of T4 into the active T3 requires glucose, and in diabetes, cells are deprived of glucose. Logically, all diabetics would be functionally hypothyroid. Providing T3 and Sugar tends to shift energy metabolism away from the oxidation of fats, back to the oxidation of sugar.”