That's my understanding of them, and why I think marketing claims of 'instant ketosis' are slightly misleading, namely you are pressing the pause button if not already glycogen depleted. The single biggest benefit is some added performance, physical and mental, while restricting carbs. There is also an argument that you may be burning less fat using them even while in natural ketosis. That said, if you are doing more and performance is going up then that is worth the trade off. It's worth checking Paul Carter, who is associated with a brand, as this appears to be his thoughts. Regarding insulin levels, I don't quite get what you mean.