You need a combination of both "you" and your "diet". The diet part in this equation is the food plan. The "you" part is what you need to do to stay on the diet.
Too often, a woman will go out and buy the latest trendiest most promising diet book. But then she is left on her own to do the "you" part.
Without the "you" part, the sticking to it part, and all that entails, what good is a food plan?