It is routine for Type 2s to be producing much higher insulin than normal when diagnosed. That is the hallmark of Type 2 diabetes. A simple blood test measuring insulin levels will confirm it. The pancreas has already been overproducing prior to diagnosis because the patient is resistant. That is why there is a lag between the problem and the diagnosis. The pancreas produces more and more insulin to keep blood sugars in the normal range as insulin resistance increases. Eventually, the resistance cannot be overcome by more production.
So the real question is how can one become less resistant, that is, more sensitive to insulin? How do you increase sensitivity to something? By giving less of it. For example, if you know someone who automatically puts a lot of salt on their food without even having tasted it, they are not sensitive enough to the taste of salt. If you remove salt from their diet for three weeks and have them try to eat the same way they formerly did, they will be shocked at how salty the food tastes. For a Type 2, the thing to do is reduce the need for insulin. There are two mechanisms for doing this. Greatly lowering the amount of foods that raise your blood sugar (carbs) reduces the need for insulin. So you are reducing the load on your body. But what about also considering the amount of time your body is under load? If you eat a very low carb diet, but you eat three meals a day, your body is still under load virtually all the time, unless you are only eating fat (because protein also produces an insulin demand, just smaller and slower). If you want there to be a time period when your body is making no demand for insulin, then fasting for a period will do it. Whether you eat all your food in an 8 hour window or you fast for 24 hours a couple of times a week (or more), the experience of many people on this forum, including myself, is that this combination (low carb + fasting) greatly improves control over blood sugars.