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What Is The Difference Between Complete And Incomplete Proteins?

the difference between complete and incomplete protein

Protein! You know you need it, you have a basic idea of where it comes from, and you are pretty sure you’re eating enough. But what is the difference between complete and incomplete proteins? How much of each kind do you need? In this article, we will dive into the nitty-gritty of protein, both incomplete and complete. You’ll walk away knowing how much protein you need to reach optimum health and fitness. 

What You Need To Know About Complete and Incomplete Proteins

Proteins are the building blocks of YOU. Your cells, organs, circulatory system, bones, skin, and hair are made with proteins. As an athlete, getting adequate levels of protein (and the right kinds of protein) is essential to proper healing, muscle recovery, strength improvement, and sufficient energy levels. When you are deficient, you will not feel your best, and your goals will feel much harder to achieve.

Proteins are made of amino acids. There are 20 amino acids that make up the various protein structures of your body. Nine of these are essential amino acids, which means your body does NOT make them on its own and needs a plentiful amount from your diet. 

The remaining 11 are non-essential amino acids, which means your body can produce them on its own when insufficient amounts are ingested. Don’t let their name fool you- non-essential amino acids are still extremely important, and should be included in your daily diet. Especially as an active individual, you need well-rounded and diverse sources of protein. Non-essential amino acids are often found in plant-based proteins as well as animal products. 

What Is The Difference Between Complete and Incomplete Proteins?

An incomplete protein is a food source that contains less than 9 of the essential amino acids. Common examples include plant-based protein sources like spinach, peas, nuts, and seeds.

A complete protein is a food source that contains ALL 9 of the essential amino acids. Common examples include meat and animal products, as well as some plant complete proteins such as quinoa and soy.

Signs You’re Not Getting Enough Protein

If you are experiencing one or more of the following symptoms below, you may be suffering from protein deficiency from not enough complete proteins. 

  • Poor/slow wound healing
  • Prolonged muscle soreness
  • Ravenous appetite
  • Difficulty building muscle
  • Muscle mass loss
  • Brittle hair
  • Bone fractures
  • Weak immune system/recurrent infections
  • Low energy
  • Muscle weakness 

A protein deficiency may occur because you are eating a lot of incomplete protein sources and not enough complete ones. Or because you are not getting enough of either. Your body needs ALL the amino acids, with the best combination having a mix of all the essential amino acids and some of the non-essential. 

Your 9 Essential Amino Acids

The following is a basic list of the 9 essential amino acids that make certain foods a complete protein source, as well as the 11 (equally important) non-essential amino acids. Proteins have hundreds of different functions, all of which are vital to whole-body wellness. You need a balance of both complete and incomplete proteins in order to thrive. 

  • Histidine: protects the nervous system, aids in the immune response, improves digestion and sexual function, and plays a role in the sleep-wake cycle. 
  • Isoleucine: highly concentrated in muscle tissue, aids energy production, boosts immune function. 
  • Leucine: vital for protein synthesis and rebuilding muscles, plays a role in wound healing. 
  • Lysine: aids the absorption of calcium, supports the production of collagen, important in protein synthesis.  
  • Methionine: helps the body to absorb minerals such as zinc and selenium, improves metabolism and detoxification. 
  • Phenylalanine: a precursor for neurotransmitters, aids in the production of other amino acids. 
  • Threonine: improves fat metabolism, supports immune system function, strengthens connective tissue. 
  • Tryptophan: important for regulating mood, sleep, and appetite. 
  • Valine: stimulates muscle regeneration and growth, helps the body to create energy. 

Non-Essential Amino Acids 

  • Alanine: helps the body convert glucose into energy
  • Arginine: supports hormone production, cell division, immune system function, wound healing, and removal of ammonia from the body
  • Asparagine: a structural protein, important for the development and function of brain cells
  • Aspartic acid: a precursor to four essential amino acids
  • Cysteine: supports antioxidant function in the body, may help support liver function
  • Glutamic acid: converts to glutamate in the body, which acts as a neurotransmitter and is important for learning and memory
  • Glutamine: aids in the synthesis of protein and lipids, transports ammonia from the body, helps to maintain the pH of the body
  • Glycine: has a calming effect on the central nervous system, may improve sleep
  • Proline: a main amino acid in a collagen protein
  • Serine: important to metabolism function, support neurotransmitter function
  • Tyrosine: a precursor to dopamine, norepinephrine, and epinephrine (adrenalin)

Complete Protein Foods vs. Incomplete Protein Foods

The most common source of complete protein is from animal products such as meat, fish, poultry, seafood, milk, and eggs. These all contain a strong blend of essential amino acids, and several non-essential amino acids as well.  

Some vegan or plant-based sources of complete protein include quinoa, soy, spirulina, and buckwheat. While beans may contain all the essential amino acids, they don’t have large amounts of certain ones like lysine. If you combine it with rice, which has high amounts of lysine, you can help to boost the protein quality of your meal.  

Beans, peas, grains, nuts and seeds, vegetables, and spinach are all incomplete protein sources. Sometimes you can combine incomplete protein foods and create “complementary proteins” which means that when eaten together, all essential amino acids are present. Some good examples of this include peanut butter on whole-wheat bread, and rice and beans. 

Complete Proteins vs BCAAS

Branched-Chain Amino Acids (BCAAS) are three amino acids that have a branched-chain molecular structure. Leucine, valine, and isoleucine are the three BCAAs that you find in fitness supplements. BCAAs are not a complete protein source because they contain only 3 of the 9 essential amino acids. They are most often used to help stimulate muscle protein synthesis. 

While BCAAs are a popular supplement, current research suggests that they do not offer full support for building and repairing muscle like a complete protein can. Most companies that make collagen protein powders and BCAA supplements save money by not adding in all the essential amino acids. This is why it’s important to check labels and make sure you are buying supplements that contain complete protein. 

How Much Protein Do I Need?

The Recommended Dietary Allowance (RDA) for protein for the average person is 0.8g per kg of body weight. To calculate your RDA for optimal protein absorption, you’ll take your body weight (in pounds) and divide it by 2.2, then multiply it by 0.8. 

For power and endurance athletes, the Academy of Nutrition and Dietetics broke this down into a suggestion of 84g - 119g for men and somewhere between 66g - 94g for women. 

Here is an equation to make it a little more simple:

  • Normal: (lbs)/2.2 x 0.8 = grams of protein recommended per day 
  • Athlete: (lbs)/2.2 x 1.2 = grams of protein recommended per day

You want to spread your protein throughout your day versus trying to consume it all at once. Most research suggests you can only absorb and utilize about 30 grams in one sitting, anyway.  Try to have a complete protein source at every meal or a combination of proteins that become a complete protein when eaten together. 

When choosing a protein supplement, keep in mind that many companies are only selling products that are incomplete proteins. 

In order to maximize the benefits of a collagen supplement, it is important that essential amino acids are added to the blend in order to create a complete protein source. All Frog Fuel collagen protein products created to be complete proteins, with all the benefits of hydrolyzed collagen and the 9 essential amino acids.