Well, if it's generally agreed that protein intake should remain fairly constant, and on a weight maintaining diet, then as fat goes up, carbs must go down and vice versa.

The book I read was clearly promoting a high fat (even saturated fat), low carb diet. Yet, undermined itself.

And, this isn't personal, but friendly discussion, your answer is a non-answer or that the answer is that there is no answer -- none that anyone, at least I, can understand.