While the argumentum ad hominem presented in this thread may be entertaining, one must admit that it's not an argument fit for proving superiority of one method over the other. I base my opinions of other people's knowledge solely on their statements and how they relate to scientific findings (i know of) as well as my own experience.
It's also quite clear that the more restricted methods used by most nutritionists work great. However, due to the vast difference between successful approaches (e.g. high fat vs. high carb diets vs. anything in between), quite obviously not all restrictions are necessary. In addition, many restrictions, such as using food items that can easily be measured regarding their macro and caloric content, are simply applied out of convenience, to meet a certain goal at a certain time.