Protein explained by science
Recently, I have received numerous questions about protein, so I thought it would be a good opportunity to provide a comprehensive overview of this important macronutrient for muscle building.
In this article, I will cover the basics of protein, commonly referred to as Protein 101, and address some of the most frequently asked protein-related questions. So, without further delay…
What is Protein?
To understand how much protein to consume and its role in the body, it is essential to have a clear understanding of what this macro is and how it functions.
Proteins are large molecules, also known as macromolecules, composed of one or more long chains of amino acids. The specific arrangement of amino acids determines the unique characteristics of each protein. Peptide bonds hold together these chains of amino acids (polypeptides).
These macronutrients play a crucial role in various cellular processes and you can find them in every cell in the human body. Saying that proteins are important would be an understatement.
When they are broken down, they yield a variety of amino acids. Amino acids are often referred to as the building blocks of protein.
There are 20 common amino acids, and 9 of them are considered essential because they cannot be synthesized by the body and must be obtained through our diet. Additionally, three amino acids—leucine, isoleucine, and valine—are known as branch-chained amino acids.
Here is a list of the 20 amino acids and their respective categories:
- Alanine
- Arginine
- Asparagine
- Aspartic acid
- Cysteine
- Glutamine
- Glutamic acid
- Glycine
- Histidine (Essential)
- Isoleucine (Essential – Branch Chained)
- Leucine (Essential – Branch Chained)
- Lysine (Essential)
- Methionine (Essential)
- Phenylalanine (Essential)
- Proline
- Serine
- Threonine (Essential)
- Tryptophan (Essential)
- Tyrosine
- Valine (Essential – Branch Chained)
Differences in Protein Quality:
Now that we understand the importance of protein, it’s worth discussing the quality of proteins from different sources.
The quality of a protein is determined by its peptide sequence. Certain ideal amino acid ratios allow humans to maximize the utilization of dietary protein. These ratios can be used to evaluate the quality of different protein sources.
Moreover, specific amino acids, such as leucine, isoleucine, and valine (branch-chained amino acids), are believed to be particularly important for protein synthesis.
How Protein Quality Is Scored:
To assess protein quality, the Protein Digestibility Corrected Amino Acid Score (PDCAAS) is commonly used. It is a chart adopted by the Food and Drug Administration (FDA) in 1993 to rate protein quality based on human amino acid requirements and digestibility. The PDCAAS is considered the best method for evaluating protein quality, while other methods like Protein Efficiency Ratio (PER) and Biological Value (BV) are deemed inferior.
The scoring system works as follows:
The PDCAAS compares the amino acid profile of a specific dietary protein to a standard amino acid profile, with a score of 1.0 being the highest quality. A score of 1.0 means that after digestion, the protein provides 100% or more of the indispensable amino acids required per unit of protein. Scores below 1.0 indicate lower protein quality.
The PDCAAS (Protein Digestibility Corrected Amino Acid Score) is a method used to evaluate the quality of a protein based on its amino acid profile and digestibility. It was adopted by the FDA in 1993 and is considered the preferred method for assessing protein quality. Other methods like Protein Efficiency Ratio (PER) and Biological Value (BV) are considered inferior by the FDA.
The PDCAAS assigns a score between 0 and 1 to proteins, with 1 being the highest quality. The score indicates the protein’s ability to provide essential amino acids in sufficient quantities. Foods like casein, egg white, soy protein, and whey have a PDCAAS score of 1.0, indicating excellent protein quality.
A few examples of protein food source quality scores (value of 1 is the highest, and 0 is the lowest)
- 1.00 casein (milk protein)
- 1.00 whey (milk protein)
- 0.99 mycoprotein
- 1.00 egg white
- 0.92 beef
- 0.91 soybeans
- 0.78 chickpeas
- 1.00 soy protein
- 0.76 fruits
- 0.75 black beans[disambiguation needed]
- 0.73 vegetables
- 0.70 Other legumes
- 0.59 cereals and derivatives
- 0.52 peanuts
- 0.42 whole wheat
How Much Daily Protein Should You Consume?
While protein quality is important, the total amount of protein consumed is also crucial. Setting daily protein intake goals based on total calories and macronutrient needs is a priority. The old recommendation of consuming 1-2 grams of protein per pound of body weight is an exaggeration. Research suggests that a range of 0.37-0.82 grams of protein per pound of body weight is sufficient for positive nitrogen balance and muscle maintenance or growth.
1g – 2g OF PROTEIN PER POUND OF BODYWEIGHT?
“You need 1g – 2g of protein per lb” I have no doubt if you’ve spent any time in the fitness community you’ve heard a version of this statement. So is it legit?
The old-school bodybuilding methodology of protein consumption was to simply eat 1 gram (on the low end) of protein per pound of body weight. What’s amazing to me is that the fitness community has deeply ingrained this concept that you rarely hear anyone question its validity! At Savage Coaching we pride ourselves on doing our best to reference science-backed fitness and nutrition advice.
So does the data agree with the gym bros?
Check out just some of these excerpts from past research.
- Walberg et al. (1988) found that 0.73g/lb was sufficient to maintain a positive nitrogen balance in weightlifters that were dieting (in a negative energy balance) over a 7-day time period.
- Tarnopolsky et al (1988) found that only 0.37g/lb was required to maintain positive nitrogen balance in elite bodybuilders over a 10-day period. 0.45g/lb was sufficient to maintain lean body mass in bodybuilders over a 2-week period. The authors suggested that 0.55g/lb was sufficient for bodybuilders.
- Lemon et al. (1992) found no differences in muscle mass or strength gains in novice bodybuilders consuming either 0.61g/lb or 1.19g/lb over a 4-week period. Based on nitrogen balance data, the authors recommended 0.75g/lb.
- Hoffman et al. (2006) found no differences in body composition, strength or resting hormonal concentrations in strength athletes consuming either 0.77g/lb or >0.91g/lb over a 3-month period.
Hopefully based off that you get the idea. The old 1g of protein per pound of body weight was clearly an exaggeration. According to these sources, the minimum effective daily requirements of protein are substantially lower than they often recommend in the fitness community. Considering the fact that it’s not uncommon for regular lifters to be consuming as much as 2g per pound of body weight. Based off the above studies that would be over double the necessary requirements.
Don’t Jump To Conclusions!
Now before you assume we are bashing the old ways. There is some value to the good old 1g per pound recommendation, and though the literature seems to contradict it, there are a few things to consider.
Like many things, there may have been some hidden wisdom in using that as a general guideline for most lifters.
What The Science Says:
Based off of most research and review studies, 0.82g/lb of protein would be the highest limit recommended (Phillips & Van Loon, 2011), and many studies, as you can see above, conclude lower than this. 0.82g/lb at this point seems to be the extreme higher end of the spectrum and is backed up with This recommendation often includes a double 95% confidence level, meaning they took the highest mean intake at which benefits were still observed and then added two standard deviations to that level to make absolutely sure all possible benefits from additional protein intake are utilized.
What About The 1g Per Pound Approach:
Well as it turns out, when you dig further into these studies, there are some stand-out limitations that could substantially change things. To save us the time of going into each one of these variables, we can reference Dr. Helms and colleagues in a meta-analysis that looked at just this. https://pubmed.ncbi.nlm.nih.gov/25028958/
According to Helms and colleagues, the requirements for trained individuals looking to build or maintain muscle mass is between 1.8g – 2.6g per kg of fat-free mass. This means their approach is basing the considerations on lean tissue rather than total weight.
What We Recommend:
For the most part, we tend to take Helm’s approach by considering a client’s lean body mass and shooting between 1.8g – 2.6g per kg. When using that approach we consider several other training and physiological variables on which end of that range we apply.
There is an exception however and it is one we find ourselves defaulting to more often than not and for most of you reading this just want a simple answer to start, this is it. Using the old-school method of 1g per lb of total body weight more often than not will land the majority of people within the same ranges recommended by Helms.
So if you don’t need to dial it in super specific with fat-free mass, keep it simple and just make sure you get at least 1g per pound.
How Much Protein Per Meal?
The notion that the body can only absorb a limited amount of protein per meal is a common myth in the fitness community. The truth is that the body can efficiently absorb amino acids from meals regardless of the size. After reaching the threshold of essential amino acids, the anabolic response of skeletal muscles increases, but the exact amount of protein absorbed is not the primary concern.
To maximize muscle synthesis, they recommend consuming approximately 15 grams of essential amino acids, with 3.2 grams coming from leucine, which plays a crucial role in stimulating muscle growth. Different protein sources have varying amounts of leucine, and consuming enough protein from a specific source can help optimize protein synthesis.
How Many Protein Meals Per Day?
Regarding nutrient timing, it is not a high-priority factor for most people. However, research suggests that protein anabolism tends to return to normal every 2-3 hours, depending on the protein source. This indicates that consuming protein at regular intervals can help maintain an elevated level of amino acids in the bloodstream and support muscle growth.
Sources:
- Effect of protein intake on strength, body composition and endocrine changes in strength/power athletes. Hoffman JR, Ratamess NA, Kang J, Falvo MJ, Faigenbaum AD. J Int Soc Sports Nutr. 2006.
- Macronutrient content of a hypoenergy diet affects nitrogen retention and muscle function in weight lifters. Walberg JL, Leidy MK, Sturgill DJ, Hinkle DE, Ritchey SJ, Sebolt DR. Int J Sports Med. 1988.
- Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. Lemon PW, Tarnopolsky MA, MacDougall JD, Atkinson SA. J Appl Physiol. 1992.
- Dietary protein for athletes: From requirements to optimum adaptation. Phillips SM, Van Loon LJ. J Sports Sci. 2011.
- Effects of exercise on dietary protein requirements. Lemon PW. Int J Sport Nutr. 1998.
- Effects of high-calorie supplements on body composition and muscular strength following resistance training. Rozenek R, Ward P, Long S, Garhammer J. J Sports Med Phys Fitness. 2002.
- Increased protein maintains nitrogen balance during exercise-induced energy deficit. Pikosky MA, Smith TJ, Grediagin A, Castaneda-Sceppa C, Byerley L, Glickman EL, Young AJ. Med Sci Sports Exerc. 2008.
- Macronutrient Intakes as Determinants of Dietary Protein and Amino Acid
