Finding the Optimal Dosages and Timing of Protein Intake for Increases in Muscle Mass & Strength

Protein is a vital macronutrient necessary for building and repairing tissues- most notably, muscle tissue. Muscle protein synthesis (MPS) is the process by which the body utilizes amino acids (the building blocks of protein) to construct new muscle proteins. This biological process is critical for the repair and remodeling of muscle fibers damaged during resistance training or intense physical activity (Witard, Bannock, & Tipton, 2021). MPS is a key component of hypertrophy which is the increase in muscle size through resistance training (Hornsby et al., 2018). For individuals aiming to increase muscle mass and strength, navigating protein intake can feel overwhelming. With so much information available on how much protein to consume and when to consume it, it’s important to focus on the key principles supported by research and practical application. Let’s break it down.

The first consideration in determining optimal protein dosage involves identifying the amount needed to maximize MPS after exercise. Moore & colleagues (2009) investigated the effects of consuming 5, 10, 20, and 40 grams egg protein following a bout of leg resistance exercise. MPS rates were measured over 4 hours post exercise. The study found that max MPS rates were achieved with the intake of 20 grams of protein, with no significant additional benefits observed at higher intakes. These findings suggest that consuming more than 20 grams of protein immediately after exercise may not further enhance MPS.

While it’s common to focus on meeting a total daily protein target, research suggests that evenly distributing protein intake throughout the day may be a more effective strategy for maximizing muscle protein synthesis. In a 2013 study by Areta and colleagues, participants consumed protein in one of three patterns following resistance exercise: 10 grams every 1.5 hours, 20 grams every 3 hours, or 40 grams every 6 hours. The researchers found that distributing protein intake evenly throughout the day at about 20 grams every 3 hours was a more effective strategy in optimizing muscle protein synthesis than consuming larger doses less frequently. These findings highlight the potential benefits of spreading protein intake throughout the day rather than consuming large, infrequent doses (Areta et al., 2013). However, it is important to consider that individual protein needs may vary depending on factors such as the type and intensity of resistance exercise performed. 

Following a full-body resistance training session, the body’s demand for protein increases to support muscle repair, recovery, and growth. MacNaughton & colleagues (2016) measured MPS rates 4 hours after a whole body resistance exercise with the ingestion of either 20 or 40 grams of protein intake immediately post-exercise. They found that the ingestion of 40 grams following the full body resistance exercise stimulated a greater MPS response as opposed to a 20 gram-dose. The results of this study could indicate that for full body resistance exercise, a protein dosage greater than 20 grams may be needed to effectively induce a maximal MPS response.

The term ‘anabolic window’ has been widely debated in the field of sports nutrition. Often referred to as the ‘protein window’, this term describes the period immediately following exercise during which muscles are believed to be most responsive to protein intake for promoting muscle repair and growth (Ivy & Ferguson-Stegall, 2013). Traditionally, it was believed that this window was narrow- lasting approximately 30 to 60 minutes post-exercise. A meta-analysis by Aragon and Schoenfeld (2013) found little support for the existence of a strict anabolic window, suggesting instead that the window for effective protein intake may extend up to 4 to 6 hours after training. Their findings indicated no significant differences in strength or hypertrophy outcomes between individuals who consumed protein immediately after exercise and those who delayed intake. This research underscores the importance of total daily protein intake as the primary factor in muscle adaptation, with nutrient timing playing a secondary role. Still consuming protein within a few hours post-exercise remains a practical and beneficial strategy for supporting recovery and muscle growth (Aragon & Schoenfeld, 2013).

Optimizing protein intake for muscle growth involves more than simply hitting a daily target- it requires thoughtful attention to timing, dosage, and distribution. Research suggests that consuming approximately 20-40 grams of high quality protein after resistance exercise may effectively stimulate muscle protein synthesis, with higher doses potentially needed following full-body training (MacNaughton et al., 2016; Moore et al., 2009). Additionally, distributing protein evenly across meals throughout the day, rather than consuming large, infrequent servings, appears to further enhance MPS (Areta et al., 2013). While the concept of a strict anabolic window has been largely debunked, consuming protein within a few hours post-exercise remains a practical strategy for supporting recovery and growth (Aragon & Schoenfeld, 2013). Ultimately, consistent, adequate daily protein intake- based on your training and body composition goals- is essential for building strength and muscle.

Citations

1. Aragon, A., & Schoenfeld, B. (2013). ‘Nutrient timing revisited: is there a post-exercise anabolic window?’, J Int Soc Sports Nutr, 10(1):5.
2. Areta, J., Burke, L., Ross, M., Camera, D., West, D., Broad, E., Jeacocke, N., Moore, D., Stellingwerf, T., Phillips, S., Hawley, J., & Coffey, V. (2013). ‘Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis’, J Physiol, 591(9), pp. 2319-2331.
3. Hornsby, W., Gentles, J., Haff, G., Stone, M., Buckner, S., Dankel, S., Bell, Z., Abe, T., & Loenneke, J. (2018). ‘What is the impact of muscle hypertrophy on strength and sport performance?’, S & C Journ, 40(6), pp. 99-111.
4. Ivy, J., & Ferguson-Stegall, L., (2013). ‘Nutrient timing: the means to improved exercise performance, recovery, and training adaptations’, Amer J Lifestyle Med, 8(4).
5. MacNaughton, L., Wardle, S., Witard, O., McGlory, C., Hamilton, D., Jeromson, S., Lawrence, C., Wallis, G., & Tipton, K. (2016). ‘The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein’. Physiol Rep, 4(15).
6. Moore, D., Robinson, M., Fry, J., Jason, T., Glover, E., Wilkinson, S., Prior, T., Tarnopolsky, M., & Philips, S. (2009). ‘Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men’, Am J Clin Nutr, 89(1), pp. 161-168.
7. Witard, C., Bannock, L., & Tipton, K. (2021). ‘Making sense of muscle protein synthesis: a focus on muscle growth during resistance training’, Intl Journ of Sport Nutrition & Ex Metab, 32(1), pp. 49-61.

Written by : Nina Billotto, MSc