Welcome Sonja! I found the book confusing in some ways too! The first time I did phaseI, I stuck to the menus in the book. The second time, I didn't, just stayed on the food lists, and didn't focus on portion sizes, but only lost 5 lbs on Phase I. That was okay, because I was more concerned about "detoxing" from sugar. After I found this site, I found the food lists and serving guides here more helpful than the book. I would say, if you are hungry, eat something, just not the whole package. Keep reading here, and ask questions, and you'll get the hang of it.
Life's a journey, not a destination.
It's easier to stay on plan than to get back on plan.