Interesting question, it had been on my mind. I've been following a strict low carb, zero (ish) protein), low calorie regime for three weeks and the alarming BG all over the place while just low carb has now rectified itself and everything seems between 5.6 and 7 until this morning. Sudden jump to 12 which I can't explain, still at around 8 (15:00) and only had veg for lunch. Sorry, just remembered, I have a leg infection after going base over apex last Thursday, leg waited until today to swell up and go hot and red. GP who I managed to see at a moments notice prescribed antibiotics so infection is probable cause.