You could be severely insulin resistant. The low carb diet will help to shed pounds, but you might need to supplement this with some moderate exercise; "Trust me i'm a Doctor" showed what 10 days of walking could do for blood sugars (the latest on iPlayer). I don't know if walking is for you, but if you can top and tail your day with this, compress your meals maybe between 10:00 and 17:00, and try and get 8 hours sleep (very important) most likely your numbers will come down proportional to the input. I could only walk at 15 minute miles initially, a year later I can do 4 at circa 11.50 in the same session - the first 2 weeks are the hardest physically as is the will power to do. Again only good advice if you are in a position to take this on.