I always say, eggs are the perfect protein source. I’m serious.
Why do I say that?
There’s this thing called Biological Value or (BV) that measures how much protein is actually absorbed by the human body.
The egg is the only food that scores a perfect score of 100. In fact, food scientists measure other protein sources against eggs as the standard for protein quality.
Alright I’m done beating off eggs now (pun intended). Now I have a question for you:
Are you one of those people who throws out the yolks of the egg?
We all know that eggs whites are almost pure protein. But what about the yolk? What does it have to offer?
Well, egg yolks contain about half of the protein contained in an entire egg, so that’s important to know. However, it also contains most of the egg’s calories in the form of fat.
So, many people throw their yolks away because they a) think they are wasted, extra calories or b) think they slow down the digestion of protein and we know rapid protein digestion translates to more efficient recovery.
Others also likely listened to a documentary that I won’t name, but it rhymes with Shut the Wealth, which says that the cholesterol in eggs is bad for you. We in the nutrition world used to think this, but that claim has since been disproven.
So then, does it matter? Are you missing out on anything by throwing out the yolk? Or is it better to just stick with the white when it comes to muscle growth?
What Does the Science Say?
A study done in 2017 took 10 men and split them into two groups. They then had each of them eat 18 grams of protein post-workout. One group got this 18 grams from just egg whites and the other group got it from whole eggs.
The scientists then set out to see how much these feedings affected muscle growth by seeing how quickly their leucine levels went up (leucine is the amino acid mainly responsible for stimulating muscle growth) and also by taking a sample of their muscle tissue to see how the size changed.
Not only that, they repeated these tests a number of times over 5 hours to see how long this effect from the egg feedings lasted.
Here’s what they found.
They saw that the men who ate whole eggs had a 42% higher level of muscle growth than those who only ate egg whites. Even though they ate the exact same amount of protein, the only thing that changed was the source.
Why though?
I wish I could give you a clear reason for the mechanism, but even the scientists who ran the study aren’t entirely sure. However, we can use our knowledge of metabolism to make some possible theories.
The most obvious one is calories. It’s the cardinal rule of bulking that’s backed by science. If you eat more calories, your body has more to work with in terms of building more tissue which means more robust muscle growth. And when we’re talking about eggs, 18 grams of protein from egg whites is a measly 75 calories while 18 grams of protein from whole eggs is 3x that at 225 calories.
However, I’m not convinced the calorie surplus alone could make such a big difference in terms of muscle synthesis.
So, another theory could be the nutrients in the egg itself. Eggs in general are packed full of nutrients, but there’s one in particular that may have a special effect on muscle gain.
Some studies suggest that omega-6 supplementation, specifically arachidonic acid, may send some messages to the muscle to grow in a mechanism that’s not completely known.
However, the amount of arachidonic acid the guys in the egg study were eating was way lower than the amount used in the arachidonic acid studies. So that theory is also hokey.
So, Which is Really Better?
As far as what the science is saying, you may be depriving your muscle of some progress by trashing your egg yolks. Not to say that whole eggs are going to be a hugely significant difference in your gains than whites, but when it comes to gaining muscle as efficiently and healthfully as possible, even the tiniest of advantages helps.
The bottom line? It doesn’t matter what form you eat your eggs in if you aren’t eating enough protein after your workout. So, make sure you’ve got your chickens in a row in that realm before you even consider worrying about details like egg yolk disposal.
However, eggs are the highest quality protein you can get in terms of how your body absorbs it and all of the extra vitamins and minerals that come with it. Not only that, most of those nutrients are in the yolk! The egg white is almost pure protein.
So, even if the science is far from conclusive, whole eggs are still an excellent food to add to your recovery repertoire either way.
If you want to learn from me exactly how to tailor your nutrition and training to gain muscle the right way, you want to check out my program The Athlete's Method.