Low-carb gurus have been telling people that insulin resistance, which is the underlying cause of type 2 diabetes, results from eating too much carbohydrate. Yet scientists have known since the 1930s that the problem can be provoked by a high-fat diet and reversed by a starchy, low-fat diet. You can read the research for yourself here.
Here's the glucose tolerance test results of a healthy person on a high-fat test diet as opposed to a high-carb diet. Notice that people who are eating a high-carb diet had much lower peak glucose levels!
This work was done in the 1930s. How long will it take before the low-carb gurus hear about it?