>> The authors assert that carbohydrate restriction was the main cause of lowered blood glucose, weight, and medicine use (weight loss was not the cause of the improvements; rather, it was one effect among others). Continuous care was required for medicine management and in order to sustain the diet, as clearly stated in the summary (emphasis mine):

Well, to be fair, they didn't make any attempt to control for improvements due to weight loss alone. They compared their results with one "lifestyle change" study and one calorie restriction study (also with carbohydrate reduction, both of which references I didn't follow) and the difference in outcomes was not that groundbreaking, I'd say.

But I'm not a doctor, or a biologist and I can't really say for sure. I'd welcome some input from a specialist on this.