The diet works and Dave know his stuff but for some people doesnt work very good becouse they need some carbs or carb loading like 4 days with cero carbs and high fats and 3 days carb up wiht fats so you can retain size, hardiness and density, also you will have a normal life feeling better and having better workouts.
I do know and i have did a lot of experiments and it works very good my way.
Well is not my way it is absully very old, Dave just adjusted to no carbs at all.