When you are training for a marathon, it is normal to load up on carbs, because you want the fuel to help get you through the race or a difficult long, training day. MarathonPal.com gives a great breakdown of WHY you need carbs and you can check it out in full, but the short version is this: "The goal of carbohydrate loading is to super load muscles with glycogen to delay fatigue and enable your to maintain high intensity exercise for longer. When competing for over 90 minutes normal glycogen stores will not be enough to maintain exercise. Carbohydrate loading is a method of increasing stored glycogen by 200-300%, thereby allowing the athlete to delay fatigue and maintain high intensity exercise for longer. Carbohydrate loading is of no benefit for sports of short duration, and is undesirable in sports with strict weight criteria."
The last line answers my friends question! Most bodybuilders are not doing high intensity exercise. Ideally, the amino acids from a pre-workout meal that's high in protein will be hitting the muscle cells at the conclusion of your workout, thus providing ample resources for muscle growth and repair. You'll also feel stronger in the gym, since protein and fat remain in your stomach longer. That being said, you can't totally skip the carbs either! Protein and unsaturated fat may be "king" when it comes to building muscle, but complex carbs have an important supporting role. By eating my breakfast of Eggology On-the-Go (which provides 4 scrambled egg whites in 95 seconds) and combining that with one slice of whole wheat toast, 45 to 90 minutes before hitting the gym, I'm ready for a great workout. And if you don't believe that this works, check out Ronnie Coleman - who uses Eggology Egg Whites as part of his daily diet routine! I think a picture is worth a thousand words!