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We all know that resistance athletes, both bodybuilders and weightlifters alike, need to consume more protein in their diet than non-athletes. But advice for how much protein to consume, how often, and when can be conflicting.
Here at Skinny Yoked, we’re all about science. So, to clarify the confusion, we did some research end ended up at the International Society of Sports Nutrition (ISSN) which published their statement on dietary nutrition and its impact on athletes that do resistance training.  This ISSN post updates some of the conclusions reached in previous posts based on some more recent research. It is the most current and up-to-date guide on exactly how much protein the body needs to recover from exercise and build new muscle.
So if you’re looking for a straightforward, research-based guide to protein consumption for athletes that do strength training, this is just the post is for you. It provides recommendations on protein consumption for resistance training athletes based on established nutrition and sports science research. It also explains why protein is important and then provides protein consumption recommendations for resistance training athletes.
Background: Why Is Protein Important?
Within the past few decades, research has consistently suggested that the protein needs of athletes, and resistance trainers/bodybuilders in particular, are higher than the average individual. [6, 8] There are several reasons for this need for greater dietary protein.
Protein is essential to the synthesis of muscle tissue. Resistance training results in micro tears in muscle cells, which are subsequently repaired by the body. In addition to repairing the damaged muscle fibers, the body creates additional muscle fibers, which leads to increased muscle strength.  Both the process of repairing and of building muscle tissues requires amino acids that are found in dietary protein. Adequate dietary protein is therefore important to support the repair and synthesis of new muscle fibers.
Supplemental Dietary Protein Seems to Enhance Performance in Athletes
Protein as an essential part of muscle development is pretty uncontroversial. It has long been recognized that adequate protein intake is a requirement for maintenance and growth of muscle mass to provide the food for the repair of muscles.  However, it has not always been clear that resistance athletes required more protein than the general population. Further, there has been some conflicting evidence with respect to whether protein over and above the amount recommended for the general public improved performance in athletes.
For example, other blogs have presented evidence, such as this study from 2014, finding that supplemental dietary protein does not seem to increases performance.  In that study, a group of 30 participants were randomly assigned to one of two groups: a group that consumed a high protein diet of two pounds of protein per pound of body weight per day, and a control group that ate as usual. The researchers reported no significant differences between the groups for body composition or performance. In other words, the high protein diet didn’t seem to make a difference for muscle growth, fat loss, or the volume of weight the athletes lifted.
But there’s a danger in relying on only one study to form conclusions, especially on one study with such a small sample size. Other researchers have found that consuming high protein diets do lead to improved athletic performance. [3, 4, 5]
In order to clarify the conflicting results, one team of researchers performed a systematic review of results from 38 primary studies.  A systematic review summarizes results from a number of studies. Systematic reviews are more reliable than any one individual study because they reflect the entire body of literature. That means their results are less susceptible to distortion because of small samples or other methodological issues.
The systematic review found that a high protein diet could lead to increased performance, but the picture was somewhat complex. 
Length of training program mattered. “Protein supplements had little or no effect on measures of strength … when programs were 4 weeks or less, whereas positive effects of protein supplements have been observed on changes in … muscle strength when training programs were 8 weeks or longer.”  In other words, if an athlete is training longer than 8 weeks, protein likely improves performance and leads to changes in muscle strength.
Level of training also matters. While consuming supplemental dietary protein did not have significant effects for untrained athletes, for highly trained athletes it did significantly increase muscle strength. As training frequency, duration, and intensity increased, protein supplementation promoted greater gains in strength.  This has been corroborated by several other studies. [6, 10, 13]
The systematic review concludes that, for athletes engaged in resistance training, the evidence supports the claim that supplemental protein intake improves performance. 
Supplemental Dietary Protein Seems to Support Changes in Body Composition
This same systematic review study found evidence that for athletes, increased protein intake led to increases in lean body mass . This is corroborated by several other studies that found that increasing protein intake above the recommended daily allowance while simultaneously restricting energy intake leads to fat tissue reductions without a loss in muscle mass. [7, 10]. Another review—this time a meta-analysis of studies, which aggregates statistical results from several studies making its findings more robust than a single experiment—found that consuming protein supplementation led to increases in lean mass and reductions in mass from fat for individuals engaged in a resistance training program. 
The overall conclusion seems to be that increasing protein consumption in combination with resistance training regimes improves lean muscle mass. When it is combined with restrictions of overall calories, it results in a reduction of fat.
Protein Intake Recommendations for Resistance Training Athletes
Great, so high dietary protein diets can help you build muscle, lose fat, and strength if you’re an athlete and exercising regularly over a long period of time. But how much should you consume?
The daily recommended dietary intake for protein for the general population is 0.36 grams per pound of bodyweight per day. But we know athletes require more protein than the general public.
Based on a large body of established research, the ISSN recommends that resistance training athletes intake a minimum of between 0.64 and 0.91 grams of protein each day for every pound of body weight as a minimum.  They suggest that these quantities of protein are sufficient for most individuals engaged in resistance training for maintaining and building muscle mass, although requirements depend on personal characteristics such as sex, age, and exercise program intensity. The ISSN further suggests that protein intake levels below 0.54 grams a day per pound of body weight is too little for resistance athletes. 
In terms of serving size, they recommend that 0.11 grams of protein per pound of bodyweight be included in each food serving, and that servings occur approximately every 3-4 hours. 
These suggested values are based on the large body of established evidence that has been conducted on the link between protein intake and performance.  However, the ISSN also recognizes that there is some newer research that suggests that even higher intakes—consuming 1.4 grams of protein per pound of body weight or more per day—may also have benefits for body composition and reducing mass from fat.  These findings are newer, meaning there is less evidence supporting these claims.
The research also seems to suggest that the timing of consumption can affect how protein consumption improves performance. Consuming protein within the hours before and after exercise seems especially helpful for improving performance. [6, 13]
Further, some research has reported that when protein is consumed shortly after exercise it is incorporated to a greater extent in skeletal muscle.  Protein intake before sleep also seems to be beneficial for performance.  While timing does have an impact on the extent to which performance improves in the context of resistance training athletes, this impact is relatively small for non-athlete populations. 
The official stance of the ISSN is “The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion; however, the anabolic effect of exercise is long-lasting (at least 24 hours), but likely diminishes with increasing time post-exercise.” In other words, protein intake is good both before and after workouts, but how beneficial may depend on the individual.
Where Should I Get My Protein From?
Most athletes will get the majority of their protein from food. Athletes are best served by trying to consume whole foods that contain all essential amino acids.  As others have suggested, plant-based sources of protein are plentiful, in addition to those that come from various types of meats. High-protein pastas are a great way to up your daily protein intake in a easy and delicious way. Protein supplements can also be a useful source of dietary protein, and, according to the ISSN, are “a practical way of ensuring intake of adequate protein quality and quantity, while minimizing caloric intake, particularly for athletes who typically complete high volumes of training.” 
There are a lot of great protein powders available, ranging from dedicated whey isolates, concentrates and blends. There is also micellar casein which is a great before-bed option as it digests slower and thus drips muscle-building amino acids over an extended period of time compared to more rapidly absorbed forms like whey isolates. We personally like consuming a blend of casein and whey to get immediate impacts combined with more sustained slow-digestion-induced impacts.
If you’re not a fan of whey here are always vegan alternatives like pea protein and soy proteins. If you don’t like whey but like animals then you can always consider something like a beef protein which is sourced from actual cows.
- Protein is essential for muscle synthesis and repair.
- High dietary protein intake improves performance and body composition for athletes but it doesn’t have an effect for non-athletes.
- The general public should consume 0.36 grams of protein for every pound of body weight every day
- Athletes should get a minimum of 0.64 – 0.91 grams of protein for every kilogram of body weight every day.
- As training frequency, intensity, and duration increase, so should protein consumption.
- Protein should ideally be consumed every 3-4 hours.
- There is some evidence that consuming protein before and after training as well as before sleeping is beneficial for performance.
- Be careful not to base conclusions off of individual research studies. Instead, look for systematic reviews and meta-analyses that summarize a body of literature.
*This post was written and researched by Ramsay Lewis.
- Antonio, Jose, Corey A. Peacock, Anya Ellerbroek, Brandon Fromhoff, and Tobin Silver. “The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals.” Journal of the International Society of Sports Nutrition 11, no. 1 (2014): 19.
- Cermak, Naomi M., Peter T. Res, Lisette C. P. G. M. de Groot, Wim H. M. Saris, and Luc J. C. Van Loon. “Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis.” The American Journal of Clinical Nutrition 96, no. 6 (2012): 1454-1464.
- Cribb, Paul J., Andrew D. Williams, and Alan Hayes. “A creatine-protein-carbohydrate supplement enhances responses to resistance training.” Medicine and Science in Sport and Exercise 39, no. 11 (2007): 1960-1968.
- Cribb, Paul J., Andrew D. Williams, Christos Stathis, Michael F. Carey, and Alan Hayes. “Effects of whey isolate, creatine and resistance training on muscle hypertrophy.” Medicine & Science in Sports & Exercise 39, no. 2 (2007): 298-307.
- Cribb, Paul J., Andrew D. Williams, Michael F. Carey, and Alan Hayes. “The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine.” International Journal of Sport Nutrition and Exercise Metabolism 16, no. 5 (2006): 494-509.
- Jäger, R., Kerksick, C. M., Campbell, B. I., Cribb, P. J., Wells, S. D., Skwiat, T. M., Purpura, M., Ziegenfuss, T. N., Ferrando, A. A., Arent, S. M. and Smith-Ryan, A. E. (2017). “International society of sports nutrition position stand: Protein and exercise.” Journal of the International Society of Sports Nutrition, 14(1), pp. 1-20. [Accessed on 14th February 2019]
- Layman, Donald K., Ellen Evans, Jamie I. Baum, Jennifer Seyler, Donna J. Erickson, and Richard A. Boileau. “Dietary protein and exercise have additive effects on body composition during weight loss in adult women.” The Journal of Nutrition 135, no. 8 (2005): 1903-1910.
- Lemon, Peter W. R. “Effect of exercise on protein requirements.” Journal of Sports Sciences 9, no. S1 (1991): 53-70.
- Lemon, Peter W. R., and David N. Proctor. “Protein intake and athletic performance.” Sports Medicine 12, no. 5 (1991): 313-325.
- Pasiakos, Stefan M., Jay J. Cao, Lee M. Margolis, Edward R. Sauter, Leah D. Whigham, James P. McClung, Jennifer C. Rood, John W. Carbone, Gerald F. Combs Jr, and Andrew J. Young. “Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: A randomized controlled trial.” The FASEB Journal 27, no. 9 (2013): 3837-3847.
- Pasiakos, Stefan M., Tom M. McLellan, and Harris R. Lieberman. “The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: a systematic review.” Sports Medicine 45, no. 1 (2015): 111-131.
- Pennings, Bart, René Koopman, Milou Beelen, Joan M. G. Senden, Wim H. M. Saris, and Luc J. C. Van Loon. “Exercising before protein intake allows for greater use of dietary protein–derived amino acids for de novo muscle protein synthesis in both young and elderly men.” The American Journal of Clinical Nutrition 93, no. 2 (2010): 322-331.
- Volek, Jeff S. “Influence of nutrition on responses to resistance training.” Medicine & Science in Sports & Exercise 36, no. 4 (2004): 689-696.