Ok, I’m guilty of this too. I was doing the egg white omelettes with wheat toast and no butter back in the day. I thought I was doing it right. It’s sad to think of all those yolks I wasted. 

The egg white, is about 90% water, and 10% protein. That’s it, there’s not much to the egg white. Egg yolks are so nutrient dense and they contain the macros and micros that you want. It’s about 60% fats, 35% protein, and the rest is carbs. Fats are good, particularly the saturated fats. Our nervous system is made primarily of fats and they are essential to survival. 

Additionally, egg yolks are a powerhouse of essential amino acids, vitamins, and minerals. For starters, they are a great source of: vitamins A, D, E, K, B1, B2, B5, folate, choline, and minerals calcium, iron, magnesium, phosphorus, potassium, selenium, and zinc. They raise HDL levels and lower triglycerides (which is what you want). 

So why have they been demonized? Cholesterol. Eggs are high in cholesterol. Let me start by saying cholesterol is good. Why would our bodies produce something that is bad for you. And oh yeah, all animals produce cholesterol. Is this an accident? I think not. In fact there is a condition called Smith-Lemli-Opitz syndrome that is a genetic mutation causing low levels of cholesterol and is deadly if not addressed. One way these patients do better is a prescription of egg yolks. So why are we told cholesterol is bad? 

It’s a long story, but the short of it is that cholesterol is transmitted by a molecule called LDL (what is typically called the ‘bad cholesterol’). It is more like a bus ushering the cholesterol into other cells. There is a ‘key card’ on the LDL’s surface; a protein called apo B. When the LDL arrives at a cell, the cell recognizes the key card, and lets the cholesterol in. Sometimes, the key card gets damaged, and the cells no longer allow the cholesterol in. This is part of what leads to plaques in arteries. So what leads to this damage? A diet high in sugar and industrial seed oils, aka the standard American diet. For more on this, check out this article. 

So as long as you avoid packaged goods and don’t have a cookie problem, egg yolks are one of the best foods you can have.