I am not a doctor, but anyone, after seeing those numbers, would probably agree with me.
Maybe your doc is trying to pimp meds. I dunno. I can't see a doc suggesting metformin with those kinds of reasonable results over a period of time.
Tell him/her to get stuffed, or to explain why he/she is suggesting it.
Well, you can say the get stuffed part after he/she gives you a reason.