inHUMAN Nutritions

A Quick Primer on Protein & Amino Acids

A Quick Primer on Protein & Amino Acids
Posted on: 2013-07-31 08:16:35 Ft.

Protein is comprised of amino acids. When digested, the body breaks up the protein source into the amino acids that comprise it. The body then recombines these amino acids into new proteins, such as muscle tissue. As you can assume, consuming enough protein throughout the day is a must for any athlete.

Essential vs. Non-Essential Amino Acids

There are 22 amino acids found in protein. These amino acids are collectively term proteinogenic (used in the production of protein). Of these amino acids, 8 are deemed essential and must be obtained from the diet. The remaining 14 are termed non-essential as they can be manufactured in the body from the essential amino acids. (Note: A non-essential amino acid can become essential in times of stress and in children.)

Essential Amino Acids

Non-Essential Amino Acids








Aspartic Acid




Glutamic Acid










Complete vs. Non-Complete Proteins

If a protein source contains all of the essential amino acids it’s deemed a “complete protein”. Animal sources, such as beef, dairy, poultry, fish and eggs, are all complete proteins. On the other hand, if the protein source is missing one or more of the essential amino acids then it’s considered an “incomplete protein”. Plants usually tend to be deficient in one of the essential amino acids. Therefore, in order to receive the full spectrum of essential amino acids in adequate amounts, vegans and vegetarians need to consume multiple sources of plant-based proteins.

Amino Acid Profiles

Every protein source will be comprised of different amino acid ratios. For example, whey is higher in leucine than eggs. However, egg is higher in phenylalanine than whey. Also, as mentioned, most plant sources are deficient in one or more essential amino acids. Therefore, once again, it’s never a bad idea to consume multiple sources of protein. 

Protein Consumption

Protein provides 4 k/cal of energy per gram. Interestingly, protein has a higher thermic effect than carbohydrates or fat. Essentially, it takes more calories (i.e. energy) to process protein. That being said, athletes who are looking to increase muscle mass and/or decrease body fat could benefit from a higher protein intake.

Carbs & Fats

Want a quick primer on carbs and fats? We’ll give you the 411 on these two other macronutrients in subsequent posts. Stay tuned.