Hi,
Wow, someone else on the zone. I can't believe it. Unfortunately, I can't answer your question, but I know where you can find answers. Check out Dr. Sear's website (Drsears.com) and ask him personally. He has a question and answer section. I am using a soy isolate protein and now have similar questions about insulin levels. Let me know when you get an answer. My guess is that if you are not feeling hungry or lethargic within the four hours after you eat the protein supplement, then you are in the zone. I probably couldn't sustain this way of eating without the soy protein powder because I use it 95% of the time for breakfast in applesauce, oatmeal or in a yogurt/berry smoothie. Good luck and keep in touch.