Dear Dr. Sears,
Q: I have just purchased the German translation of your first book, “The Zone,” and I enjoyed it very much and am planning to start this diet ASAP. But one question still arises: You wrote that the Zone is reached if the amount of insulin (triggered by eating carbs) and glucagon (triggered by eating protein) is in a specific balance. But doesn't the amount of those hormones depend also on the time the body needs to digest the foods? For example, the time the body needs to digest casein or soy protein is much longer than the time the body needs to digest whey protein. Won't that also influence the balance of insulin and glucagon? I wonder if the balance between insulin and glucagon in a meal consisting of an apple and a certain amount of whey protein is the same as in a meal consisting of an apple and a certain amount of soy protein.
Matthias B., Hamburg, Germany
Dear Matthias,
A: You are correct in your analysis, and this is why I suggest eating the protein first, followed by eating the carbohydrates. However satiety is as much a consequence of hormone sensors in the gut relaying information to hypothalamus as it is from the balance of insulin and glucagon. Although whey protein is rapidly digested, it is also rapidly metabolized so that it produces much less satiety than casein or soy protein. The apple and the soy protein would be a better choice.