For a long time, it has been unquestioningly accepted that dietary fat is dangerous to people with diabetes and that diabetics should lean heavily on carbohydrates in their diets. This is slowly changing. But change is very slow.
There is a commonly-held belief that high carbohydrate consumption is necessary because the brain and central nervous system must have glucose as its energy source. Yet this belief is contrary to the fact that the liver, intestines and kidneys can -- and does -- convert protein into glucose for the brain.
"Until very recently, researchers were not comparing the effects of low carbohydrate diets to the ADA low fat/low protein diet. Recent results consistently support low carbohydrate, high protein- diets–not only for blood sugar control, but also with regard to weight loss and cardiac risk. Many of these studies are posted on the Web site of the Nutrition and Metabolism Society, at www.nutritionandmetabolism.com."
http://www.diabeteshealth.com/read/2007/04/24/5141/why-the-low-carb-diet-is-best