I'm not a fan of the Zone...but I know you can adjust blocks or whatever they call them to get higher intake of calories. A zone at a standard level is VERY low in calories....but you can make the calories high and keep the ratios. But...I don't do zone and like my carbs pwo. ANY diet too low in calories is not ideal for athletic performance....even high carbohydrate low calorie.
I'd be more interested in a study comparing diet protocols of the SAME amount of calories and different ratios of macroutrient intake rather than you using every thread as an opportunity to dismiss everything but a high carb diet as ideal.