As you may already know, your body is technically a big, protein-based biological machine.
Aside from water, protein is the most common element in the body and more importantly, it regulates a variety of vital processes. In a sense, protein is the building block of most of your tissues, enzymes, and hormones.
However, not all protein is created equal, meaning that the protein coming from different food sources, will be metabolized by the body in a slightly different way. There are high-quality sources of protein, but also, low-quality ones.
You might wonder why I am going to tell you the technical bit but trust me, it will explain why you see the same foods in certain based diets again and again.
The Technical Bit: The Biological Value (BV) Of Proteins
Proteins' biological value is used to determine how well they are digested, absorbed, and preserved by the body after consumption. To put it simply, the biological value can be used to demonstrate the efficiency of the consumed protein.
Now, there are two primary measures that help us understand more about the biological value of proteins.
Proteins are made up of amino acids. There are 20 amino acids, 9 of which are essential, meaning that the body needs them but can’t produce them on its own. Tthe more complete a certain food’s amino acid profile is, the higher its biological value.
The second thing used to measure the biological value of proteins is protein retention, or in other words, how long the protein stays in the body.
The BV Standard
Now, in nutritional science, the biological value of proteins goes on a scale from 0 to 100.
Whole eggs (yolk and egg white) are the standard for the biological value of proteins, measuring at 95-100 BV.
If we take the yolk out of the egg, the biological value drops with 5-10 points, down to 90-95.
With whole eggs being the golden BV standard, other foods are compared to them, in order to determine the bioavailability, as opposed to optimal quality protein (whole eggs).
Note: Whey/isolate protein supplements have a BV of 100+.
Now, this theoretical information is important, but it brings us to the next logical question.
What Are The Best Protein Sources?
Below are listed the biological value of the most common protein sources that are on the market - food and supplements:
Whey isolate protein blends - 100-150 BV
Whole eggs - BV 100
Cow milk - BV 91
Egg white - BV 88
Fish - BV 83
Beef - BV 80
Chicken - BV 79
Casein - BV 77
Rice - BV 74
Soy - BV 59
Beans & legumes - BV 49
Peanuts - BV 43
Now, what this 12-point table means for you, is that your primary sources of protein should be the ones on the top of the list, which have higher biological value.
Nevertheless, you can combine those with other, lesser bioavailable sources of protein, such as plant protein.
Ultimately, your best bet is to put a couple of food sources at the core of your protein intake, while also diversifying with a variety of other food sources.
The biological value of proteins (BV) tells us more about the amino acid content of each food, as well as how long its protein is retained in the body and how efficiently it is used.
Animal sources of protein appear to be superior, due to the better amino acid profile, as well as overall bioavailability.
This is why, if you are not vegetarian or vegan, foods like beef, eggs, fish, and chicken, should make up the majority of your daily protein intake.