IIRC, type 2 diabetes comes from immense sugar imbalance that eventually overwhelms your pancreas. this can come from the obvious things like overindulgence in sugary sodas, candies, pastries, or anything that is loaded with sugar, especially in today's industry. It could also come from too many grains in the diet period, whole or otherwise.

I have no idea how red meat would be causing diabetes. The growth hormones in red meat can cause tons of other issues, like cancer for instance, but I just don't see how it would contribute to diabetes.