yes - phase 1 is designed to get your body to start reacting to blood sugar levels and insulin as normal, and your digestive system back to normal. It is not just a "kick start weight loss", phase 1 is the weight loss phase only. so it is the phase to get you within your ideal weight according to BMI range. 8 weeks is hardly that long!

phase 2 is how you should eat for the rest of your life. it reintroduces and broadens the types of foods you can eat,

Some people will take longer, some people will take a shorter amount of time, everybodies body is different.

I would strongly suggest you finish reading the book, and consult the numerous in depth posts about GI and GL and other very useful resources and websites.

All your questions are answered on this forum in very recent posts - just check through the last 10 or so threads.