The Gracie Diet is designed for Martial Artists while the 5-6 small meals a day is designed for bodybuilders and fitness enthusiasts.
Martial Artists do a great deal of cardio, strength training, and practices everyday and needs tremendous amount of energy. Martial Artists aren't that concerned about how they look or how defined their muscles are, or at least it's not just their primary concern. Hence, eating much more than the usual is just normal. This is where most people tend to get confused, eat more in lesser intervals or eat less frequently? The answer will depend as to what your goal is and you mode of training. The amount of food intake and the level and intensity of exercise must be proportional.
But of course, to live a healthy lifestyle and to keep the body to it's peak condition, a healthy and balanced diet is still heavily required.