It's not really in the book. In DANDR he just says to eat high fat and adiquet protien. In Atkins for life he seems to assume people were eating high fat and high protien, so he talks about redusing both as carbs increase.

From what people say on this bored, and I think soemone even emailed the Atkins site, around 65-70% of calories form fat while in induciton. As you raise carbs in OWL, that percentage will slightly drop since you try to keep calories the same while adding carbs. Otherwise you are just adding more food and calories on top of what your already eating.