Protein & Muscle Building Simplified
By: Dr. Marc Morris CSCS & Taylor Leonhardt
There are many benefits that come with building muscle – like improved athletic performance and physique development. Beyond the aesthetic, muscle moves us, burns fat and stores carbohydrate. Gaining muscle seems straightforward – break it down by training, build it up by eating protein, do this repeatedly – but is it really that simple?
The balance between muscle building and muscle breakdown determines muscle mass (Morton, McGlory, & Phillips, 2015). Comparatively, muscle building is more influenced by diet and exercise than muscle breakdown, making it more important when trying to gain muscle. Spending time in the gym is easy – most of us should probably be paying the gym rent instead of a membership – however, covering your protein bases can be difficult.
Variables concerning protein intake have differing impact on muscle gain. The total, dose, timing, quality, and co-ingestion with carbohydrates all influence your ability to gain muscle - but how important are these variables?
1. Total intake. Besides resistance training, eating enough protein is the most effective way to maximize muscle gain (Schoenfeld, Aragon, & Krieger, 2013). An increased daily protein intake, within the range of 1.8 – 2.7 gram per kilogram (g/kg) of body weight per day, is optimal for muscle building (Phillips & Van Loon, 2011).
APPLICATION: If you cannot eat enough protein through whole food sources, protein supplements can help.
2. Dose. To maximize muscle growth, consume protein at a dose of 0.4 g/kg of body weight at each meal. Unfortunately, increasing the dose does not result in an increased rate of muscle growth (Morton et al., 2015).
APPLICATION: Calculate your required total and split the dose throughout the day. Remember, total daily protein takes care of most of this process, but after that spreading it out over the course of the day can be helpful
3. Timing. Exercise stimulates muscle building for an extended period of time (~up to 48 hours), making eating protein consumption this period important (Morton et al., 2015; S. M. Phillips, Tipton, Aarsland, Wolf, & Wolfe, 1997). However, as discussed daily protein intake, not timing, determines muscle growth (Schoenfeld et al., 2013). Even so, splitting up protein between meals and snacks (~0.4 g/kg at a time) both after resistance training and spread throughout the day is encouraged.
APPLICATION: Without hitting a daily total, protein timing doesn’t matter too much – similarly, if you were hoping to save money and reduced spending during the week, but blew it all on the weekend, would you save? No, hitting this optimal dose in the 24-hour nutrition window matters the most. Also, if you plan on exercising fasted, taking a branched chain amino acid (BCAA) can prevent extended muscle breakdown.
4. Quality. Isolated protein sources have different effects on your muscles - whey and soy digest quickly causing a momentary spike muscle growth potential (Reitelseder et al., 2011; Tang, Moore, Kujbida, Tarnopolsky, & Phillips, 2009). Whereas Casein digests slowly, suppressing the breakdown of muscle, (Boirie et al., 1997; Pennings et al., 2011). Additionally, not all proteins contain the same profile, so it’s recommended to vary your sources (meat, plant, dairy etc).
APPLICATION: Since whey digests fast, consuming it is ideal and convenient around your workout.
5. Co-ingestion with carbohydrates. Consuming carbohydrates stimulates insulin, a hormone that promotes muscle growth, so consuming them together results in more potential for muscle growth than consuming protein alone. However, the level of insulin produced by protein and carbohydrate is beyond what is required to maximize MPS, meaning only protein is needed to capitalize on muscle growth (Greenhaff et al., 2008; Trommelen, Groen, Hamer, de Groot, & van Loon, 2015).
APPLICATION: Just because it’s not essential for muscle gain, doesn’t mean it doesn’t help – depending on your body composition goals and carbohydrate requirements, consume upwards of 30 to 60 grams of carbohydrate around your workout.
Research around protein and muscle building suggests different ways to optimize muscle gain. To cover your bases, consume a diet with an sufficient daily protein total, spaced out when possible, to provide the nutritional needs for muscle gain.
Boirie, Y., Dangin, M., Gachon, P., Vasson, M.-P., Maubois, J.-L., & Beaufrere, B. (1997). Slow and fast dietary proteins differently modulate postprandial protein accretion. Proceedings of the National Academy of Sciences, 94, 14930–14935.
Churchward-Venne, T. A., Breen, L., Di Donato, D. M., Hector, A. J., Mitchell, C. J., Moore, D. R., … Phillips, S. M. (2014). Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double-blind, randomized trial. American Journal of Clinical Nutrition, 99, 276–286.
Greenhaff, P. L., Karagounis, L. G., Peirce, N., Simpson, E. J., Hazell, M., Layfield, R., … Rennie, M. J. (2008). Disassociation between the effects of amino acids and insulin on signaling, ubiquitin ligases, and protein turnover in human muscle. AJP: Endocrinology and Metabolism, 295, E595–E604.
Morton, R. W., McGlory, C., & Phillips, S. M. (2015). Nutritional interventions to augment resistance training-induced skeletal muscle hypertrophy. Frontiers in Physiology, 6.
Pennings, B., Boirie, Y., Senden, J. M., Gijsen, A. P., Kuipers, H., & van Loon, L. J. (2011). Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men. American Journal of Clinical Nutrition, 93, 997–1005.
Phillips, S. M., Tipton, K. D., Aarsland, A., Wolf, S. E., & Wolfe, R. R. (1997). Mixed muscle protein synthesis and breakdown after resistance exercise in humans. The American Journal of Physiology, 273, E99–107.
Phillips, S. M., & Van Loon, L. J. C. (2011). Dietary protein for athletes: From requirements to optimum adaptation. Journal of Sports Sciences, 29, S29–S38.
Reitelseder, S., Agergaard, J., Doessing, S., Helmark, I. C., Lund, P., Kristensen, N. B., … Holm, L. (2011). Whey and casein labeled with L-[1-13C]leucine and muscle protein synthesis: effect of resistance exercise and protein ingestion. AJP: Endocrinology and Metabolism, 300, E231–E242.
Schoenfeld, B., Aragon, A., & Krieger, J. W. (2013). The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. Journal of the International Society of Sports Nutrition, 10, 53.
Tang, J. E., Moore, D. R., Kujbida, G. W., Tarnopolsky, M. A., & Phillips, S. M. (2009). Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. Journal of Applied Physiology, 107, 987–992.
Trommelen, J., Groen, B. B. L., Hamer, H. M., de Groot, L. C. P. G. M., & van Loon, L. J. C. (2015). MECHANISMS IN ENDOCRINOLOGY: Exogenous insulin does not increase muscle protein synthesis rate when administered systemically: a systematic review. European Journal of Endocrinology, 173, R25–R34.
Dr. Marc Morris PhD, CSCS is a Strength and Health coach living in Saskatoon. Marc’s experience in fitness is varied: he is a competitive powerlifter and International Team coach, and a national level physique competitor. Marc leverages his athletic experience and credentials in biochemistry and human nutrition to provide evidence-based but practical recommendations to clients and the fitness community. Marc can be found on Instagram @marcwmorris, Facebook @Marc W. Morris and reached by email at firstname.lastname@example.org