There is an obvious question that arises after reading this article.
Your body needs energy. This energy can come from carbs, fat or protein. Regardless of the source, the only way the energy can get to your internal organs is via blood glucose. Insulin is released by the pancreas in response to blood glucose. Even if your diet is 100% fat, that fat is converted into glucose via ketogenesis/gluconeogenesis before the energy can be used.
What reason is there to think that consuming 2000 calories/day of "slow release" complex carbs will result in significantly different levels of insulin from consuming the same 2000 calories/day of fat and protein?