As far as I'm aware it's been recognised for at least a couple of hundred years (ref John Rollo in the 1790s , and Banting in the 1800s with his Letter on Corpulence) that low(er) carb diets are one of the best ways of managing diabetes. The first low carb diabetic cookery book was actually published in 1917, this type of diet being the only(?) diabetic treatment before the discovery of insulin. So this current obsession with insisting on stuffing diabetics with high carb food is completely beyond my comprehension. when there's plenty of long-term evidence there that low carb can and does work. 
My understanding is that while our bodies are quite capable of using both carbs and fats for energy, we don't actually need any carbs. What we DO need is a minimum amount of glucose to fuel part of our brains, and our livers will provide this. I've definitely learned that my brain runs far better on a regular supply of fat generated ketones than entirely on glucose - after 5-6 years of pre diagnosis zombie brain fog generated by eating a
not-of-my-choosing very high carb diet.
My understanding is that while our bodies are quite capable of using both carbs and fats for energy, we don't actually need any carbs. What we DO need is a minimum amount of glucose to fuel part of our brains, and our livers will provide this. I've definitely learned that my brain runs far better on a regular supply of fat generated ketones than entirely on glucose - after 5-6 years of pre diagnosis zombie brain fog generated by eating a
not-of-my-choosing very high carb diet.
