As far as I know, let me know if wrong, most studies show you cardio endurance goes down with zero carbs. I know there are a bunch of athletes who say they perform best with a carnivore diet.
As for the look on zero carbs, I kind of think it makes you stringy and hollowed out in the face and probably older looking too. Having watched bodybuilding I think the hardest athletes are the "high" carb ones. There was the European pro, forgot his name just now, who says he eats 1000 grams of carbs all the way to the show, and I think he carb loads with insulin with at least double the carbs. It's insane. No bloat too and very ripped but part of that is genetics.
Imagine if Makkawy would so that diet with while increasing protein by 30% and then included 150 carbs with insulin before every workout. Say 10iu insulin and 4iu growth. I would predict he would have leaned out further while putting on mass.