Protein intake is a topic I get questions on daily. With the popularity of high protein diets in today's society, I feel it is important to have a solid understanding of what protein is, and what it does in your body.
In this article, I will break down the science of proteins into easy to understand analogies to help you get a grasp on what it is, where it should come from, and how it can fit into your personal diet.
The Protein Basics
Protein is arguably the most important nutrient for your body. Proteins are found literally everywhere in your system. From your muscle tissues, to the enzymes that digest your food, to your skin cells, and even within your blood.
When we take protein in our body through the foods we eat, it gets broken down into smaller compounds called amino acids. Of the 20 amino acids found in the foods we eat, 9 of these are essential.
The Essential Amino Acids Include
- Histidine*
- Isoleucine
- Leucine
- Valine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
The Non-Essential Amino Acids Include
- Alanine
- Arginine*
- Asparagine
- Aspartic Acid
- Cysteine
- Glutamic Acid
- Glutamine
- Glycine
- Proline
- Serine
- Tyrosine*
An essential amino acid is one that must be provided from your diet. The other 11 amino acids can be created by your body and are not considered essential. Failing to obtain enough of even 1 of the 11 essential amino acids, those that we cannot make, results in a breaking down of the body's proteins (i.e. muscles!) to obtain the one amino acid that is needed.
Unfortunately, humans also have no system of storing excess amino acids. What this means is we must take in amino acids on a daily basis to provide the amino acids needed for the body's various functions.
| Note: Arginine is considered essential only in young children and not in adults. |
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There are basically two types of proteins that are of concern to us while grasping the protein basics:
- Complete proteins
- Incomplete proteins
Think of it as the keyboard that is in front of you representing protein. It is only a complete keyboard if all the keys are present; much like a protein is only considered a complete protein when all the "keys" are present.
Think of the keys on this keyboard as amino acids, the building blocks of proteins. Each one is slightly different but they all come together to form a keyboard. Like proteins, some keyboards are better than others. They have more keys, maybe they have one that plays music, or one that automatically connects you to the internet.
However, all you need to make a complete keyboard (complete protein) is all the letters, a spacebar, some numbers, and a few function keys. As I said above, we need protein in order to build tissues.
Animal Sources
So what better place to get the protein needed to build tissues than to eat animal tissue.
Let's just call it meat as there's something gross about thinking of eating animal tissues. Think of all the protein that comes from animal sources as being a complete keyboard. It has all the amino acids needed to make a complete protein.
Plant Sources
Plant sources are different however and do not always contain the amino acids needed to make a complete protein. In fact, only one plant source of protein, soy protein, is a complete protein.
Because most all plant sources of protein are incomplete, those of us who follow a vegetarian diet have to use food combinations to get a complete protein. Or, you can sleep in a bed of steaks in hopes of absorbing the essential amino acids.
For most of us, though, the steak bed is too cold. So let's just look at food combinations. For example, let's say A, B, C, and D represent individual essential amino acids. In a complete protein it would look like ABCD. In an incomplete protein it would look like ABC, or DBA, etc.
So, if rice for example provides AB, and beans provide CD, when eaten together they provide the same essential amino acids as a complete protein would; ABCD. Therefore vegetarians must use food combining to ensure they are receiving all the essential amino acids their body needs.
How Much Protein Do I Need In My Diet?
The recommended amount of protein for sedentary adults (low physical activity) is 0.8 grams per kilogram of bodyweight or .36 grams per pound of bodyweight. This amount is what the average, person should consume to obtain what is known as nitrogen balance.
Nitrogen balance means that your body is taking in the same amount of protein that it is breaking down which happens when you replace skin cells, repair tissues, or replace the lining to your small intestine.
So, is this enough for an active person? Good question! Being in nitrogen balance is fine for every day life. However, you, being so smart, are here on this site to become a lean mean fat fighting, muscle gaining machine. Both males and females need to strive to gain even small amounts of muscles if they want to accelerate their fat loss and help change their body composition.
The question of whether bodybuilders and athletes need more than this recommended amount is still up for debate. What is now known is that excess protein (<40% of total Calories) in the diet does not cause kidney damage or other adverse effects as originally was thought.
Another benefit of taking in extra protein than is recommended is it requires more energy to break down than carbohydrates. This means your body will be burning more calories to break down and absorb protein, than it would other nutrients.
Because it takes more energy to break down, this also means more time. The result is protein is held in the stomach longer than equal amounts of many carbohydrates. This increases what is known as satiety from meals. Satiety is a measurement of satisfaction or "fullness" from a meal. This is especially beneficial to those of us seeking weight reduction through appetite control.
While it is extremely important to not compromise the intake of other essential nutrients such as fiber, complex carbohydrates, and vitamins and minerals, we can see that it can be quite beneficial to increase protein intake while looking to improve body composition.
Much like there are better sources of carbohydrates than others, there are better sources of proteins than others. And similar to how carbohydrates are rated on the glycemic index, proteins are graded on their quality on several scales.
The most common and easy to understand grading system is what is known as the Biological Value of a protein. This simply means that the higher a protein's biological value (BV), the more nitrogen your body can absorb, use, and retain.
As a result, proteins with the highest BV promote the most lean muscle gains. But who needs lean muscle? If you don't, just close up the article and return to the couch. If you do, check out this chart listing the biological values of common foods.
Biological Value Of Common Foods
| Food | Biological Value |
| Eggs (whole) Eggs (whites) Chicken / Turkey Fish Lean Beef Cow's Milk Unpolished Rice Brown Rice White Rice Peanuts Peas Whole Wheat Soy beans Whole-grain Wheat Peanuts Corn Dry Beans White Potato |
100 88 79 70 69 60 59 57 56 55 55 49 47 44 43 36 34 34 |
Note: The biological value does not represent a percentage. Egg protein is given a biological value of 100 however only approximately 94% is digested and absorbed for use by the body. Because this is the highest percent from natural food sources it is given the reference biological value of 100 and every other food is rated in comparison.
As a result, some protein supplements have a higher biological value than 100. The following is a list of how these supplements match up.
Protein Supplement Ratings
| Protein Supplement | Biological Value |
| Whey Protein Isolate Whey Protein Concentrate Casein Soy |
159 104 77 74 |
How Can We Use This In Our Everyday Diets?
The higher biological value proteins will be better absorbed and provide more amino acids which can be used for the body's various needs. With that being said, it is important to consume a variety of protein sources in your diet.
Some lower biological value proteins will be digested slower and can help increase satiety further. This can be a benefit depending on when it is being consumed. Find out when the best times for your body to be taking in protein is by speaking with your own nutrition professional today.
The key is to find what amount of protein will be right for your body and fit your lifestyle. It is very important to work with a professional while considering any change in your diet to ensure you other nutrients are not sacrificed.
Feel free to contact me with any questions or comments, and remember keep training hard! It's not a game!
Keep Training Hard!