Here is some harsh, but needed advice.
You just need to eat. You THINK you eat a lot, but you don't. Trust me. All of my skinny friends seem to be the same way.
Here is some additional, easier to take, but solid advice:
- Count your calories. You will be surprised that you eat a lot less than you think.
- Finish everything you start to eat. (don't leave meals half done or just pick at them)
- Do no cardio. Its just going to be counterproductive.
- 200 Grams of protein won't hurt you.
- 45% carbs, 35% protein, 20% fat sounds perfect for you, as long as you are taking in 200-250 grams of protein. That means about 300 grams of carbs, and prob 60 grams of fat. Eat around 2700 calories a day until you start gaining mass. Then bump it up slightly. Don't let a day pass by when you don't get your 2700 calories.
- IMO, fullbody workouts tend to be better for losing weight. I would do a split routine where you do chest/triceps one day, back and biceps the other day, and legs on the third day. You need to let your muscles rest for around 7 days to allow them time to grow. A fullbody routine would probably be counterproductive.
- Eat at least SIX regular meals a day. (how else are you going to get your 2700 calories?) At your current weight, you need around 2200 calories just to maintain your weight. You need to eat at least 500 more calories a day to put on muscle. Almost no one that tries to build muscle eats only 3 meals a day, even when dieting!
- Honestly, don't worry about the supplements at this point. The only thing I would start with is Whey protein and some creatine monohydrate. Food alone will put on more muscle than any of those supplements.
- Don't worry about nitrogen balance. Your food intake will take care of that.
- Don't be afraid of cholesterol and saturated fat. Those are both used by your body to make testosterone.
You sir are in a lucky boat. Since you are so skinny, you can just eat heavy and lift hard and you will do nothing but put on muscle. You can bulk for a good long time before you would be considered 'fat'. Lucky bastard.
If you notice a theme of all the advice above. FOOD is all you need to put on some serious muscle and size. Just be consistent with your diet and your workouts.
I hope this helps. I'm always jealous of guys that start out skinny. You will get to see all the progress you are making because there is very little fat covering your muscle.