Many personal trainers and exercise gurus recommend protein supplementation to build muscle. Their recommendations usually suggest ingesting a bolus of protein (perhaps 25-40 g) after a workout. They will cite anecdotal reports of enhanced muscle building and increased strength following this regime. Some noted health authorities, famous athletes and celebrities may also endorse protein supplementation and be employed by companies that make protein-enriched food products. As scientists however, we need to know what properly controlled, peer-reviewed research has to say about this topic.
Some basic considerations are useful to clarify the issue of protein supplementation. First, do most people get enough protein in their diets? If not, then protein supplementation would seem to be promising. Second, do athletes need more protein in their diets than the RDA and if so, do most athletes consume enough protein from regular foods to support activity and muscle building? Third, does increasing protein intake support muscle growth, and if so, when should extra protein be consumed, before, during or after a workout? And lastly, if one consumes more protein, do the amino acids produced from protein breakdown preferentially travel to muscle and improve muscle physiology?
Nutrition scientists have considered these issues in detailed investigations using animal models and in human clinical trials. It turns out that most individuals in the U.S consume more protein than the RDA. Studies have shown that athletes have higher demands (up to 2-2.5 times higher) for dietary proteins, especially strength and endurance athletes, but since they consume more calories each day, they can usually meet protein needs by consuming a normal, varied diet. Concerning protein increasing muscle mass and strength, studies have shown that exercising (i.e. using) muscles increases these parameters and that increasing protein intake alone will not have the desired effects. There is evidence however, that a modest amount of protein consumed during or after a vigorous workout (as part of a long term resistance-type training program) will enhance muscle repair and could have some effect on muscle mass and strength (Am. J. Clin. Nutr. 96(6): 1454-64, 2012). It is however important to keep in mind that if protein is consumed in excess of energy need, it will ultimately be metabolically converted into triglycerides and stored in adipose tissue.
Given these facts, do you think consuming excess protein is going to have a positive influence on your athletic abilities? Could consuming excess protein before or after a workout have a placebo effect? What about if one is a vegan? Do vegans have higher protein requirements? Are vegan diets typically lower in protein content? Does decreasing carbohydrate intake and substituting protein sound like a sound strategy to improve athletic performance? Why or why not? These are all important issues that should be considered as one develops a diet that supports athletic performance and maximizes muscle strength and endurance.