Robb Wolf is the co-owner and founder of CrossFit NorCal. He has also been studying nutrition for a long time and offers nutrition seminars all over North America.
In this video, which is a basic introduction to the Zone, Robb explains that the most acute benefit of the Zone approach to food is the accuracy and precision with which food is consumed.
There are three macronutrients that greatly affect the workings of the body: Protein, carbohydrate, and fat. With the Zone block system, you can know exactly the ratio of each at all times throughout the day. Zone blocks normalize the various differences in macronutrient effect, such that one block of sugar affects insulin to the same degree that one block of zucchini does.
No matter which approach to managing your blocks you follow, following a precise system of managing food is essential to understanding the effects of food on all levels of performance, fitness, and health.