Now, I know this is coming out VERY late today, but remember, from my food journal earlier today, I’m playing catch up this week, from my time off, changing my schedule and all that. In fact, that food journal should have been posted yesterday! Ugh! 😩 Well, it’ll all work out in the end, right? 👍
Can you believe we FINALLY finished up with carbohydrates? I wrote the very first carbohydrate post on February 12, 2017, just a short 6 months ago. Yikes! Well, now it’s time to move on to the next macronutrient, PROTEIN!
What is protein?
By definition, protein, also known as peptide, is: “a nitrogen-containing macronutrient made from amino acids. ” (1)
We know from my first carbohydrate article, that carbs are made up of smaller units known as monosaccharides. Proteins are made up of smaller units called amino acids.
What is an amino acid?
An amino acid, by definition is: “A nutrient composed of a central carbon bonded to an amino group, carboxylic acid group, and a side-chain group (R-group).” (1)
If that sounds like a bunch of gobbledygook, don’t worry. It’s not important for you to remember that. What you need to remember is that amino acids are the building blocks of protein. It’s these small particles that differentiate one protein from another. Different proteins contain different types of amino acids.
Types of amino acids (1)
The body needs 20 unique amino acids to make the required bodily proteins and function properly. These 20 amino acids are broken down into 3 groups, essential and non-essential and conditionally essential.
There are 9 amino acids that are considered ESSENTIAL. This means they must be acquired from food, because the body cannot make them.
These 9 are as follows:
The remaining 11 amino acids are considered non-essential because the body can produce them. However, under certain circumstances, such as genetics or disease, the body is unable to produce certain amino acids. In these cases, those amino acids become “conditionally essential”, meaning they must be consumed.
There are 6 conditionally essential amino acids:
There are 5 non-essential amino acids:
- aspartic acid
- glutamic acid
Complete protein vs incomplete protein (1)
Proteins are broken down into 2 groups based on the content of amino acids. A protein is considered COMPLETE if it contains proper amounts of all 9 essential amino acids. On the other hand, if a protein contains low amounts of one or more amino acids, it is considered INCOMPLETE.
Generally, animal proteins are considered COMPLETE, and also called HIGH QUALITY PROTEIN, where as plant proteins are considered INCOMPLETE and called LOW QUALITY PROTEIN. However, there are a few exceptions to this rule. Which we will discuss in a minute.
Complimentary Proteins (1)
Anyone who doesn’t consume animal protein can combine incomplete proteins together to make a complete protein. This practice is known as protein complementation, and is practiced all over the world. Essentially what this means is that certain plant foods “compliment” other plant foods.
Beans and rice is a common example of this practice. But why do they make a complete protein? This is because beans and other legumes lack proper amounts of methionine, but have lots of lysine. On the other hand, rice lacks lysine, but has lots of methionine. So, together, they combine to make a complete protein. It is indicated by many people in the vegan/vegetarian community that these foods do not need to be eaten at the same time. Eating a wide variety of plant foods high in protein is key. (6)
Here is a chart to give you a few examples of complimentary proteins:
How much protein do you need? (2,3,4)
Obviously, this question varies from person to person. Some people need quite a bit, while others can get by on just a little. It really comes down to metabolism and how well your body digests and absorbs protein.
However, the current Institute of Medicine recommends 0.8 grams of protein per kilogram of body weight. This comes out to approximately 8 grams of protein for every 20 pounds of body weight. The current US government RDA for protein is 46 grams per day for women over 19 and 56 grams per day for men over 19.
This may sound like a lot, but compared to what most Americans eat, it’s relatively little. A 3 ounce serving of chicken breast contains approximately 25 grams of protein.
Sources of complete vegetable protein (5)
These 8 plant foods contain all 9 essential amino acids and are considered a complete protein.
- Quinoa – 8.14 grams per cup
- Amaranth – 9.35 grams per cup
- Soybeans – 22 grams per cup
- Buckwheat – 23 grams per cup
- Hempseed – 31.56 grams per 100 g
- Chia seeds – 16.54 grams per 100 g
- Blue-green algae – 4 grams per tablespoon
- Spirulina – 4 grams per tablespoon
That’s all I have for you tonight regarding proteins.
Let me know if you have any questions.
- McGuire, Michelle; Beerman, Kathy A.. Nutritional Sciences: From Fundamentals to Food Cengage Textbook. Kindle Edition.