It's the whites of eggs that contain the most protein. The yolks have protein too and also a lot of fats. I only eat whole eggs because plain egg whites don't seem all that palatable to me.
Actually, the yolk contains half the protein of the egg. My best friend made that mistake when he counted his protein intake. He separated his yolks from the whites and trashed the yolk.
We'd split 6 dozen eggs, when he went to Sam's Club. He was trying to lose weight; while, I was trying to gain weight.
I crunched the numbers and he was off, by the factor of counting egg whites as whole eggs.
Whoever came up with the idea to separate the yolk needs to be strung up. Remember that Vince Gironda got ripped to the bone on steak and eggs. If I'm not mistaken, he even blended up the shells and consume them with his shakes.