We’ve all watched that famous scene of Rocky Balboa cracking copious amounts of raw eggs into a glass, and then slamming it down before stepping out the door to begin his run. Most of you reading this article are probably well aware of why he did this, however, was this actually the best approach? Was Rocky limiting his muscular “gains” by choosing to consume them in raw form, instead of cooking them?
Rocky is a huge source of motivation and inspiration for me, and Sylvester if you’re reading this, no disrespect, but research shows us that the protein in raw eggs, is significantly less digestible, compared to it’s cooked counterpart.
Lets take a look at a study…
Digestibility of Cooked vs. Raw Egg Protein in Humans
(I will cite the full study at the end of this article for those interested)
Essentially in this study, the researchers wanted to look at 3 main things (I am only going to cover 2 of them here, because the 3rd is irrelevant to this article):
1. They wanted to determine the amount of nitrogen which went un-digested after consuming a meal containing a sufficient amount of egg protein.
2. They wanted to see if heat-pretreatment (aka cooking) the eggs, increased the efficiency of the protein’s digestion and absorption.
How They Performed the Study
The researchers took 5 people (subjects), otherwise healthy besides having an ileostomy, and had them consume 2 identical meals containing both egg-whites and egg yolks (meal macros were: 25 grams protein, 5.56 grams fat, negligible carbs).
The only difference between the 2 meals, was that one was raw, uncooked egg-whites/egg-yolk, and the other egg-whites/egg-yolk, were cooked (each meal was exactly the same other than this).
Without getting into the nitty-gritty details of how they assessed the subjects (again, the full study is cited at the end of this article), the researchers had them come into the lab after having not eaten anything for 12 hours, and then fed them one of the two meals described above. From here, the researchers monitored the subjects off-and-on for the next 24 hours. They waited 1 week, and then did this same thing again, however this time with the other meal.
What They Found…
They actually found a couple of very interesting things:
The true digestibility of raw egg protein was significantly less, compared to that of cooked egg protein. On average, the amount of raw egg protein that was absorbed, was only 51%, compared to almost 91% of the cooked egg protein.
This provides us with two very interesting details:
1. Almost 50% of the 25 grams of raw egg white protein was unabsorbed. This means, you are only “getting” about 12.5 grams of protein, compared to the 25 grams you thought you were getting.
2. The true digestibility of cooked egg protein is only 91%. Although 91% sounds like a lot, and it is, it still isn’t 100%, which is what many people teach the digestibility of egg protein is.
What’s the Reason for the Difference?
The researchers speculated that the higher digestibility of cooked egg protein may be due to structural changes in the protein molecule from heating it. These changes may enable our digestive enzymes to gain greater access to the peptide bonds. Further, the researchers suggested that the reduced digestibility of raw egg white, is at least partially due to the presence of trypsin (a digestive enzyme that breaks down protein) inhibitors, contained in raw egg white.
Overall, this looked to be a pretty sound study. There were only two major downsides I noticed with it: One, was the small number of subjects (5), and the other, was that the egg protein was eaten in isolation, and not in conjunction with other foods, which is how we normally consume food (as a part of a meal). This second limitation is purely speculation, and is based on the notion that if the egg protein were eaten alongside other food sources, different digestive enzymes which would have been secreted, may have been able to increase the digestibility of the raw egg protein. However, given the amount of control the researchers had over the study and these participants, plus the methods they used to collect and analyze the data, these results look promising.
Take Home Message
Whatever our goal is, building new lean-tissue, preserving the loss of muscle while dieting, chasing a new 1 RM, protein is important. This is true for both quantity and quality, and anything that interferes with either of these two, can potentially effect the outcome of achieving our goal. I didn’t write this article to try to convince you to never eat raw eggs. I simply wanted to provide you with information, so that you can better make the decision for yourself, about what approaches you’d like to use.
I hope you benefited, and enjoyed reading this article. If there is anything you’d like me to write about, feel free to leave it in the comments section below.
Resources
Evenepoel P, Geypens B, Luypaerts A, Hiele M, Ghoos Y, Rutgeert P. Digestibility of cooked and raw egg protein in humans as assessed by stable isotope techniques. J Nutr 1998;128:1716–22.
Great article! I also appreciate you insight on the study design. Thanks!
Would this pertain to the way in which you cook eggs? I.e. A sliding scale of protein digestibility when cooked sunny side up (low end) vs scrambled/overhard/hard boiled (high end)?
My question is if the raw egg isn’t “absorbed then where is it going? Does that 50% of it just pass through without providing energy like insoluble fiber? If it is not absorbed wouldn’t you have some pretty serious toilet experiences?
If you cook the eggs sunnyside-up, is the yoke considered cooked, or died or have to be hard-fried. Is bringing the time up to temperature enough even though it’s still runny? Thanks for any clarification. Signed, Sly
Eating raw eggs is not hurting your gains! Old school bodybuilders consumed eggs raw for more than just protein. If that was the case, we would just use protein powder and call it a day. Eggs contain a glycoprotein called follistatin, which inhibits myostatin, a protein found in the blood that inhibits muscle cell growth. This alongside other muscle-building properties of follistatin make consuming tons of eggs very beneficial for your muscle gains.
one mistake:
“1. Almost 50% of the 25 grams of raw egg white protein was unabsorbed. ”
It seems to me that te whole white egg protein was unabsorbed: supposing that the whole yolk protein was absorbed that leads us to the conclussion that there is no room for egg white protein.
Ok, that is supposing that the yolk protein is easier to absorbe than the egg white one, and that the problem is with this one.
On the otther hand this is a quite bad example of bad science: only 5 subjects, not separating yolk and egg white, not testing other ways of preparing the egg like whipping, not eating alongside other foods, etc….
So how come this study doesn’t take into considering that the majority of the weight of the raw egg is going to be water so if you’re giving somone 25 grams of cooked egg and someone 25 grams of raw eggs of course the protein will be higher in the cooked because the water is removed and you’re getting more protein per gram. Now if you got two identical eggs and tested it that way would be better experiment.
Not to mention only 5 subjects and people go around quoting this study as fact.