FAQ
Protein is an essential macronutrient that is found throughout the body—in muscle, bone, skin, hair, and virtually every other body part or tissue. It makes up the enzymes that power many chemical reactions and the hemoglobin that carries oxygen in your blood. Protein is made from twenty-plus amino acids. About half of those, known as indispensable or essential amino acids, must come from food or supplements as the body cannot produce those itself.
Protein is an essential macronutrient that is found throughout the body—in muscle, bone, skin, hair, and virtually every other body part or tissue. It makes up the enzymes that power many chemical reactions and the hemoglobin that carries oxygen in your blood. Protein is made from twenty-plus amino acids. About half of those, known as indispensable or essential amino acids, must come from food or supplements as the body cannot produce those itself.
Resistance training is an important part of a complete exercise regimen. Consuming the appropriate amount and type of protein to maintain and build muscle is just as important. Muscle is built when the net protein balance is positive - muscle protein synthesis exceeds muscle protein breakdown.
To increase muscle mass in combination with physical activity, it is recommended that a person that lifts weights regularly or is training for a running or cycling event eat a range of 1.2-1.7 grams of protein per kilogram of body weight per day, or 0.5 to 0.8 grams per pound of body weight. Consequently, a 75-kilogram individual’s protein intake should be between 90 grams to 128 grams.
Resistance training is an important part of a complete exercise regimen. Consuming the appropriate amount and type of protein to maintain and build muscle is just as important. Muscle is built when the net protein balance is positive - muscle protein synthesis exceeds muscle protein breakdown.
To increase muscle mass in combination with physical activity, it is recommended that a person that lifts weights regularly or is training for a running or cycling event eat a range of 1.2-1.7 grams of protein per kilogram of body weight per day, or 0.5 to 0.8 grams per pound of body weight. Consequently, a 75-kilogram individual’s protein intake should be between 90 grams to 128 grams.
We can get protein from animal or plant sources. Animal sources high in protein are meats, fish, dairy, eggs. Plant sources of protein are legumes, nuts, seeds, some vegetables and grains.
We can get protein from animal or plant sources. Animal sources high in protein are meats, fish, dairy, eggs. Plant sources of protein are legumes, nuts, seeds, some vegetables and grains.
Proteins are comprised of three types of amino acids. Indispensable amino acids, also known as essential amino acids, are not synthesized by the body and must come from the diet. Dispensable amino acids, also known as nonessential amino acids, most of the time are produced by the body in sufficient amounts under normal, healthy conditions.
The third group of amino acids are conditionally indispensable amino acids which in the presence of certain human disease states or underlying physiological stress such as non-healing wounds, supplementation often is required to achieve an adequate supply. Most plant proteins contain sufficient amounts of dispensable and conditionally dispensable amino acids. Nonetheless, plant protein sources contain relatively less indispensable amino acids than animal protein sources.
Another thing to consider when evaluating the different protein sources is the accompanying macro and micronutrients in the protein food, which include different types of fats, carbohydrates, sodium, and other components. For example, some meats provide unhealthy amounts of saturated fats and sodium. Research has consistently found that both unprocessed and processed red meat are linked to higher risks of cardiovascular disease and diabetes. One meta-analysis found that replacing red meat with healthy plant proteins decreased the risk of cardiovascular disease.
It is also important to consider that plant-based protein is better for the environment due to its relatively lower greenhouse gas emission than animal-based protein. For example, beef is associated with about 100 times higher greenhouse emission per 100 grams of protein than pea and dairy sources as cheese and milk are associated with about 20 times higher greenhouse gas emissions than pea.
Proteins are comprised of three types of amino acids. Indispensable amino acids, also known as essential amino acids, are not synthesized by the body and must come from the diet. Dispensable amino acids, also known as nonessential amino acids, most of the time are produced by the body in sufficient amounts under normal, healthy conditions.
The third group of amino acids are conditionally indispensable amino acids which in the presence of certain human disease states or underlying physiological stress such as non-healing wounds, supplementation often is required to achieve an adequate supply. Most plant proteins contain sufficient amounts of dispensable and conditionally dispensable amino acids. Nonetheless, plant protein sources contain relatively less indispensable amino acids than animal protein sources.
Another thing to consider when evaluating the different protein sources is the accompanying macro and micronutrients in the protein food, which include different types of fats, carbohydrates, sodium, and other components. For example, some meats provide unhealthy amounts of saturated fats and sodium. Research has consistently found that both unprocessed and processed red meat are linked to higher risks of cardiovascular disease and diabetes. One meta-analysis found that replacing red meat with healthy plant proteins decreased the risk of cardiovascular disease.
It is also important to consider that plant-based protein is better for the environment due to its relatively lower greenhouse gas emission than animal-based protein. For example, beef is associated with about 100 times higher greenhouse emission per 100 grams of protein than pea and dairy sources as cheese and milk are associated with about 20 times higher greenhouse gas emissions than pea.
To gain muscle, you need protein which contains amino acids in amounts that more closely matches the amounts in the muscle tissue. As discussed above, the different protein sources have different amounts of the different amino acids. Typically, most animal protein sources have sufficient amounts of all 3 types of amino acids and this is why they are called complete proteins.
Conversely, some plant-based proteins do not contain adequate levels of some indispensable amino acids. This is not to say that plant proteins are useless for the purposes of building muscle, rather the muscle building properties of a specific protein are determined by the amount of the least represented indispensable amino acid relative to complete proteins.
It is also important to consider that most people consume different foods throughout the day and in some instances, they can end up combining different amino acids from few plant protein sources into a complete protein “package”.
To gain muscle, you need protein which contains amino acids in amounts that more closely matches the amounts in the muscle tissue. As discussed above, the different protein sources have different amounts of the different amino acids. Typically, most animal protein sources have sufficient amounts of all 3 types of amino acids and this is why they are called complete proteins.
Conversely, some plant-based proteins do not contain adequate levels of some indispensable amino acids. This is not to say that plant proteins are useless for the purposes of building muscle, rather the muscle building properties of a specific protein are determined by the amount of the least represented indispensable amino acid relative to complete proteins.
It is also important to consider that most people consume different foods throughout the day and in some instances, they can end up combining different amino acids from few plant protein sources into a complete protein “package”.
Research & Clinical Trials
There is a number of studies on the effects of protein and some of the findings are conflicting. However, not all studies are created equal. Some use a very small sample size of people and others are flawed for a variety of reasons. This is why in answering the questions above we referred to studies that used a larger sample size of people and were directed to answer the specific question of interest.
Participants: male, 18 to 35 years old.
The purpose of this study was to compare the impact of oral supplementation with plant (Pea) protein on muscle thickness relative to animal protein (Whey) and placebo (a substance that has no therapeutic effect).
One hundred and sixty-one males, age 18 to 35 years were enrolled in the study and underwent 12 weeks of resistance training on upper limb muscles. The group of men was split into 3 smaller groups. One of the groups was supplemented with 25g. of plant (Pea) protein, another with 25g. of animal (Whey) protein and the third group was given 25g. of the substance that had no therapeutic effect (placebo) twice a day during a 12-week training period. Muscle thickness of the biceps was evaluated using ultrasonography, and strength was measured on an isokinetic dynamometer.
Results showed a statistically significant increases in thickness for the groups that were supplemented with plant and animal protein relative to placebo and no statistically significant difference between the groups supplemented with plant and animal protein. Muscle strength also increased with time with no statistical difference between groups.
In conclusion, the study demonstrated that supplementation with plant (Pea) protein promoted a greater increase of muscle thickness as compared to placebo and since no difference was obtained between the two protein groups, plant (Pea) proteins could be used as an alternative to animal (Whey) based dietary products.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/25628520/
Participants: male, 18 to 35 years old.
The purpose of this study was to compare the impact of oral supplementation with plant (Pea) protein on muscle thickness relative to animal protein (Whey) and placebo (a substance that has no therapeutic effect).
One hundred and sixty-one males, age 18 to 35 years were enrolled in the study and underwent 12 weeks of resistance training on upper limb muscles. The group of men was split into 3 smaller groups. One of the groups was supplemented with 25g. of plant (Pea) protein, another with 25g. of animal (Whey) protein and the third group was given 25g. of the substance that had no therapeutic effect (placebo) twice a day during a 12-week training period. Muscle thickness of the biceps was evaluated using ultrasonography, and strength was measured on an isokinetic dynamometer.
Results showed a statistically significant increases in thickness for the groups that were supplemented with plant and animal protein relative to placebo and no statistically significant difference between the groups supplemented with plant and animal protein. Muscle strength also increased with time with no statistical difference between groups.
In conclusion, the study demonstrated that supplementation with plant (Pea) protein promoted a greater increase of muscle thickness as compared to placebo and since no difference was obtained between the two protein groups, plant (Pea) proteins could be used as an alternative to animal (Whey) based dietary products.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/25628520/
Participants: male, age 18-55 years old.
The purpose of the study was to compare plant (Pea) protein and animal (Whey) protein versus water-only supplementation on muscle damage and other markers during a 5-day period after a 90-min exercise bout in 92 non-athletic non-obese males ages 18-55 years.
The participants were split in 3 groups. One of the groups was supplemented with animal (Whey) protein, another with plant(Pea) protein and the third with water only.
Supplementation with Whey protein significantly attenuated post-exercise blood levels for biomarkers of muscle damage compared to water-only; pea protein versus water supplementation had an intermediate non-significant effect and no significant differences between whey and pea protein were found. Whey and pea protein compared to water supplementation had no significant effects on post-exercise delayed onset of muscle soreness and the fitness tests.
In conclusion, high intake of whey protein for 5 days after intensive exercise mitigated the efflux of muscle damage biomarkers, with the intake of pea protein having an intermediate effect.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/32784847/
Participants: male, age 18-55 years old.
The purpose of the study was to compare plant (Pea) protein and animal (Whey) protein versus water-only supplementation on muscle damage and other markers during a 5-day period after a 90-min exercise bout in 92 non-athletic non-obese males ages 18-55 years.
The participants were split in 3 groups. One of the groups was supplemented with animal (Whey) protein, another with plant(Pea) protein and the third with water only.
Supplementation with Whey protein significantly attenuated post-exercise blood levels for biomarkers of muscle damage compared to water-only; pea protein versus water supplementation had an intermediate non-significant effect and no significant differences between whey and pea protein were found. Whey and pea protein compared to water supplementation had no significant effects on post-exercise delayed onset of muscle soreness and the fitness tests.
In conclusion, high intake of whey protein for 5 days after intensive exercise mitigated the efflux of muscle damage biomarkers, with the intake of pea protein having an intermediate effect.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/32784847/
Participants*: male, age 68 – 76 years old
*Sample size is small (31 people)
The objectives of the study was to determine the impact of consuming different kinds of protein supplements on muscle protein synthesis when consumed above the recommended dietary allowance.
Thirty-one healthy older males consumed a controlled diet with protein intake set at the recommended daily allowance. Participants were split in 3 groups and assigned to consume an additional 25 g. of animal(whey) protein for the first group, 25g. of plant(Pea) protein for the second group, and 25g. of collagen protein for the third group consumed twice daily.
The results showed that muscle protein synthesis was increased during supplemental with whey and pea when compared with the recommended daily allowance and remained unchanged with collagen.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/38762187/
Participants*: male, age 68 – 76 years old
*Sample size is small (31 people)
The objectives of the study was to determine the impact of consuming different kinds of protein supplements on muscle protein synthesis when consumed above the recommended dietary allowance.
Thirty-one healthy older males consumed a controlled diet with protein intake set at the recommended daily allowance. Participants were split in 3 groups and assigned to consume an additional 25 g. of animal(whey) protein for the first group, 25g. of plant(Pea) protein for the second group, and 25g. of collagen protein for the third group consumed twice daily.
The results showed that muscle protein synthesis was increased during supplemental with whey and pea when compared with the recommended daily allowance and remained unchanged with collagen.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/38762187/
Participants: male and female, age 20 – 70 years old
The objective of this study was to determine whether 4 weeks of protein intake in place of a sugary drink lowers office and daytime blood pressure.
The study compared consumption of 3 × 20 grams of protein per day which consisted of 20% pea, 20% soy, 30% egg, and 30% milk-protein isolate compared with 3 × 20 g of carbohydrates per day in the form of maltodextrin. Protein or maltodextrin substituted a sugar-sweetened drink that the participants used to consume daily. A total of 94 men and women with untreated elevated blood pressure completed the study of which 51 were in the maltodextrin group and 43 were in the protein group.
The study found that office systolic blood pressure and diastolic blood pressure were respectively 4.9 and 2.7 mm Hg lower, respectively, in the protein group. Daytime systolic blood pressure was 4.6 mm Hg lower in the protein group, whereas daytime diastolic blood pressure did not differ between groups.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/22357725/
Participants: male and female, age 20 – 70 years old
The objective of this study was to determine whether 4 weeks of protein intake in place of a sugary drink lowers office and daytime blood pressure.
The study compared consumption of 3 × 20 grams of protein per day which consisted of 20% pea, 20% soy, 30% egg, and 30% milk-protein isolate compared with 3 × 20 g of carbohydrates per day in the form of maltodextrin. Protein or maltodextrin substituted a sugar-sweetened drink that the participants used to consume daily. A total of 94 men and women with untreated elevated blood pressure completed the study of which 51 were in the maltodextrin group and 43 were in the protein group.
The study found that office systolic blood pressure and diastolic blood pressure were respectively 4.9 and 2.7 mm Hg lower, respectively, in the protein group. Daytime systolic blood pressure was 4.6 mm Hg lower in the protein group, whereas daytime diastolic blood pressure did not differ between groups.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/22357725/
Participants: male and female, 65+ years old.
The objectives of the study were to investigate the effect of protein supplementation alone or combined with light-intensity or heavy-load resistance exercise on muscle size, strength, and function in older adults.
During a 1-year trial, 184 healthy older adults completed the study. They were randomly assigned to 1 of 5 interventions: 1) carbohydrate supplementation; 2) collagen protein supplementation; 3) whey protein supplementation; 4) light-intensity resistance training 3-5 times per week with whey protein supplementation; and 5) heavy resistance training 3 times weekly with whey protein supplementation. Protein supplements contained 20 g protein + 10 g carbohydrate, whereas the carbohydrate only groups were supplemented only with 30 g of carbohydrates. All intervention groups received the supplement twice daily.
The primary outcome was change in the quadriceps muscle cross-sectional area. Secondary outcomes included measures of lower extremity strength and power, functional capabilities, and body composition. Supplementation without exercise did not affect measurements of the muscle in interest. Supplementation of whey protein combined with heavy resistance training improved the muscle size and knee strength relative to whey protein supplementation only. Light exercise training in combination with whey protein supplementation increased knee strength compared to whey protein supplementation only but did not improve muscle size.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/33564844/
Participants: male and female, 65+ years old.
The objectives of the study were to investigate the effect of protein supplementation alone or combined with light-intensity or heavy-load resistance exercise on muscle size, strength, and function in older adults.
During a 1-year trial, 184 healthy older adults completed the study. They were randomly assigned to 1 of 5 interventions: 1) carbohydrate supplementation; 2) collagen protein supplementation; 3) whey protein supplementation; 4) light-intensity resistance training 3-5 times per week with whey protein supplementation; and 5) heavy resistance training 3 times weekly with whey protein supplementation. Protein supplements contained 20 g protein + 10 g carbohydrate, whereas the carbohydrate only groups were supplemented only with 30 g of carbohydrates. All intervention groups received the supplement twice daily.
The primary outcome was change in the quadriceps muscle cross-sectional area. Secondary outcomes included measures of lower extremity strength and power, functional capabilities, and body composition. Supplementation without exercise did not affect measurements of the muscle in interest. Supplementation of whey protein combined with heavy resistance training improved the muscle size and knee strength relative to whey protein supplementation only. Light exercise training in combination with whey protein supplementation increased knee strength compared to whey protein supplementation only but did not improve muscle size.
The full article can be found here: https://pubmed.ncbi.nlm.nih.gov/33564844/
Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987-992.
Castellanos VH, Litchford MD, Campbell WW. Modular protein supplements and their application to long-term care. Nutr Clin Pract. 2006;21(5):485–504.
Schaafsma G. The protein digestibility-corrected amino acid score. J Nutr. 2000;130(7):1865S–1867S.
National Academy of Sciences, Institute of Medicine, Food and Nutrition Board. Protein and amino acids. In: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids: Food and Nutrition Board: National Academy of Sciences. Washington, DC: National Academy Press;2005.
FAO/WHO Expert Consultation. Protein Quality Evaluation: Food and Agriculture Organization of the United Nations, FAO Food and Nutrition Paper No. 51. Rome, Italy: Food and Agriculture Organization;1991.
Babault, N., Païzis, C., Deley, G., Guérin-Deremaux, L., Saniez, M. H., Lefranc-Millot, C., & Allaert, F. A. (2015). Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. Journal of the International Society of Sports Nutrition, 12(1). https://doi.org/10.1186/s12970-014-0064-5
Nieman, D.C.; Zwetsloot, K.A.; Simonson, A.J.; Hoyle, A.T.; Wang, X.; Nelson, H.K.; Lefranc-Millot, C.; Guérin-Deremaux, L. Effects of Whey and Pea Protein Supplementation on Post-Eccentric Exercise Muscle Damage: A Randomized Trial. Nutrients 2020, 12, 2382. https://doi.org/10.3390/nu12082382
James McKendry, Caroline V Lowisz, Arraksana Nanthakumar, Meaghan MacDonald, Changhyun Lim, Brad S Currier, Stuart M Phillips, The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial, The American Journal of Clinical Nutrition, 2024, ISSN 0002-9165, https://doi.org/10.1016/j.ajcnut.2024.05.009
Teunissen-Beekman KF, Dopheide J, Geleijnse JM, Bakker SJ, Brink EJ, de Leeuw PW, van Baak MA. Protein supplementation lowers blood pressure in overweight adults: effect of dietary proteins on blood pressure (PROPRES), a randomized trial. Am J Clin Nutr. 2012 Apr;95(4):966-71. doi: 10.3945/ajcn.111.029116. Epub 2012 Feb 22. PMID: 22357725.
Mertz KH, Reitelseder S, Bechshoeft R, Bulow J, Højfeldt G, Jensen M, Schacht SR, Lind MV, Rasmussen MA, Mikkelsen UR, Tetens I, Engelsen SB, Nielsen DS, Jespersen AP, Holm L. The effect of daily protein supplementation, with or without resistance training for 1 year, on muscle size, strength, and function in healthy older adults: A randomized controlled trial. Am J Clin Nutr. 2021 Apr 6;113(4):790-800. doi: 10.1093/ajcn/nqaa372. PMID: 33564844.
Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987-992.
Castellanos VH, Litchford MD, Campbell WW. Modular protein supplements and their application to long-term care. Nutr Clin Pract. 2006;21(5):485–504.
Schaafsma G. The protein digestibility-corrected amino acid score. J Nutr. 2000;130(7):1865S–1867S.
National Academy of Sciences, Institute of Medicine, Food and Nutrition Board. Protein and amino acids. In: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids: Food and Nutrition Board: National Academy of Sciences. Washington, DC: National Academy Press;2005.
FAO/WHO Expert Consultation. Protein Quality Evaluation: Food and Agriculture Organization of the United Nations, FAO Food and Nutrition Paper No. 51. Rome, Italy: Food and Agriculture Organization;1991.
Babault, N., Païzis, C., Deley, G., Guérin-Deremaux, L., Saniez, M. H., Lefranc-Millot, C., & Allaert, F. A. (2015). Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. Journal of the International Society of Sports Nutrition, 12(1). https://doi.org/10.1186/s12970-014-0064-5
Nieman, D.C.; Zwetsloot, K.A.; Simonson, A.J.; Hoyle, A.T.; Wang, X.; Nelson, H.K.; Lefranc-Millot, C.; Guérin-Deremaux, L. Effects of Whey and Pea Protein Supplementation on Post-Eccentric Exercise Muscle Damage: A Randomized Trial. Nutrients 2020, 12, 2382. https://doi.org/10.3390/nu12082382
James McKendry, Caroline V Lowisz, Arraksana Nanthakumar, Meaghan MacDonald, Changhyun Lim, Brad S Currier, Stuart M Phillips, The effects of whey, pea, and collagen protein supplementation beyond the recommended dietary allowance on integrated myofibrillar protein synthetic rates in older males: a randomized controlled trial, The American Journal of Clinical Nutrition, 2024, ISSN 0002-9165, https://doi.org/10.1016/j.ajcnut.2024.05.009
Teunissen-Beekman KF, Dopheide J, Geleijnse JM, Bakker SJ, Brink EJ, de Leeuw PW, van Baak MA. Protein supplementation lowers blood pressure in overweight adults: effect of dietary proteins on blood pressure (PROPRES), a randomized trial. Am J Clin Nutr. 2012 Apr;95(4):966-71. doi: 10.3945/ajcn.111.029116. Epub 2012 Feb 22. PMID: 22357725.
Mertz KH, Reitelseder S, Bechshoeft R, Bulow J, Højfeldt G, Jensen M, Schacht SR, Lind MV, Rasmussen MA, Mikkelsen UR, Tetens I, Engelsen SB, Nielsen DS, Jespersen AP, Holm L. The effect of daily protein supplementation, with or without resistance training for 1 year, on muscle size, strength, and function in healthy older adults: A randomized controlled trial. Am J Clin Nutr. 2021 Apr 6;113(4):790-800. doi: 10.1093/ajcn/nqaa372. PMID: 33564844.
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