DEAR DR. ROACH: What is the main cause for insulin resistance? I was diagnosed with Type 2 diabetes about five years ago. I’ve maintained a consistent weight under 200 pounds, and I’m only 5’, 9” tall. I was able to get my A1C level down to 7.2percent last summer, but in late fall, my numbers started spiking, even with insulin. I now find myself injecting crazy amounts of insulin just to maintain …