If a diet raises more questions than answers, then it's not all that simple. The only confusing thing is that this is actually a book written by two very serious and real nutritional experts, who are also doctors by formal education. But their logic is quite simple.
David Zinczenko and Peter Moore started from the fact that the day is divided into thirds: 8 hours for sleeping, 8 hours for work, and 8 hours for leisure activities. According to them, people gain weight because our daily routine doesn't follow this. Most people sleep 10 hours and spend 14 hours eating.
That's why both experts suggest a diet that has no restrictions on the quantity and type of food, it is essential to eat at the same time, at the same pace, and quantity. Choose any 8 hours in the day when you are allowed to eat (not gorge!), outside of the set time frame, only water is allowed.
Of course, you are not completely free regarding the quantity, and the number of calories consumed daily is still limited, but the key finding of this diet is: routine and discipline do not make you gain weight, everything else does.