I tried several dietary modifications following the first year after my diagnosis. My sugar was lingering around 18-19 (27 without insulin) and I was happy to have it between 14 or 15 on some days. After cutting out milk (cold turkey), I started to see numbers below 10, and my A1C went from 13 to 7.3. Note that I still over-eat and replaced milk with other carbs.
So that was the good news. The bad news is that...well, I'm still here and I still stab myself daily, so giving up milk wasn't a cure, but it cut my numbers in HALF. I can wake up to 5-7 and peak at 12, but note that I eat 200+ g of carbs daily and I'm not a body builder nor an athlete. I also have psoriasis, and had it before becoming diabetic. Some years ago I gave gluten free a try, and my face cleared up and had more energy all day. Then depression struck me, and went back to eating **** food. There's not one day pass by asking myself how could I have been so stupid? It may or may not have triggered the autoimmune conditions I have today, but my experience with milk and gluten tells me that they likely did.