Doubt his diabetes is new, particularly at his age. Although glucose is checked with typical bloodwork - which almost always includes either a basic or comprehensive metabolic panel, bloodwork is not frequently conducted fasting for most physicians, at least not outpatient (at least not in the US), so glucose can be somewhat elevated and chalked up to having eaten something high in carbs recently.

Unless and until a hemaglobin A1C is checked further studies to rule out diabetes wouldn't be conducted. And unless glucose is way out of whack, an A1C might not even be conducted.

I hypothesize - without any outside evidence whatsoever and having not even read anything much on the matter (this to cover my humiliation if there is already something out there that refutes this) - that he wanted to see what his labs were and asked for an A1C since he HAD been on a ketogenic diet. Perhaps he thought it would prove the benefits of the diet, who knows.

All of this said, I'm a nurse and I will say that, when you can even get a patient to agree to it, a low-carb life-style vastly improves blood sugar. It doesn't "cure" diabetes type II. But you aren't looking for a cure, you are looking for control AND consistency of blood sugar. And when you can achieve normal blood sugar without insulin and then without oral meds, that's pretty remarkable.