Just a reminder that excess proteins and particular proteins also cause insulin rise, just like carbohydrates.
Also a cephalic insulin response occurs when the pancreas begins to secrete insulin before the “meal” actually gets into the bloodstream – the usual step required for the pancreas to secrete insulin. In other words, the anticipation of the meal leads to the release of insulin. This is the appetite kicking in, reducing blood glucose in preparation to the expectation of food. More indication the the brain has influence.