I'm not sure how they think that saturated fats are going to increase insulin resistance more than high CARBS which stimulate the direct release of insulin. Although the fiber does blunt the insulin response, yes.
"However, increments in insulin sensitivity may be more directly related to loss of intramyocellular or omental fat rather than loss of total body weight per se."
Exercise does the best job given a decent diet. Only high intensity exercise shows significant elimination of intracellular triglycerides