Optimising Protein Intake for Size and Strength: 5 Broscience Myths Put to Bed

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What you know about protein, bro?

As a consequence of its central importance to muscle building, size and strength development, protein has been at the center of some of the greatest broscience myths of all time – eating every two hours, whey post-workout, the body can only absorb 30g at a time, bro…etc.

So, let’s set the record straight on these issues: what type of protein is optimal, what kind of frequency is best, and how much overall do you actually need? But first, let me indulge the inner geek (if you’ve no interest in the mechanics, skip the next section).

Resistance Exercise and Pathways of Muscle Protein Synthesis – A Brief Primer

The balance of muscle protein synthesis (MPS) and muscle protein breakdown (MPB) is regulated by multiple signaling pathways. Two of the most important are the mammalian target of rapamycin complex 1 (mTORC1) and AMP-activated protein kinase (AMPK) (Burd et al., 2011; Dreyer et al., 2006).

These pathways each have different interactions with resistance training. During training, AMPK inhibits the activation of the mTORC1 pathway (Dreyer et al., 2006). This inhibition is released in the 60-minute period post-training, facilitating MPS signaling through activation of mTORC1 pathway enzymes, in particular p70S6K and 4E-BP1 (Ibid.).

There are two factors that activate the anabolic response and mTORC1 pathway: loading [resistance exercise] and nutrients [amino acids] (Atherton & Smith, 2012). The take home point here is that while providing amino acids will increase MPS even at rest, resistance training has an additive effect on muscle protein synthesis and prolongs the increase in MPS West el al., 2011). As long as amino acids are provided through protein feeding, muscle protein synthesis following resistance training can remain elevated for up to 24-hours (Burd et al., 2011).

So, in order for you to maximize dem gainzzz, you need to consider meal timing, what type of protein is best, and how much you need to eat.

Timing Protein – Bro Myth no.1: you have to slam protein in as soon as your last set is over!

No, you don’t. You don’t even need to slam it in within the hour. In the period post resistance training, MPS will remain maximally elevated for 1 to 3 hours (Reidy & Rasmussen, 2016). Whether you consume protein 1 hour after, or 3 hours after, the anabolic response will be similar (Rasmussen et al., 2000).

Remember that protein, AMPK? It inhibits MPS during your workout, and is then released within the first hour following training (Dreyer et al., 2006). A really tight window of consuming protein in less than an hour either side of resistance training doesn’t appear to be necessary to enhance your adaptation to training (Schonfeld, Aragon & Krieger, 2013).

Ok, what about pre-workout then? There definitely appears to be a benefit to performing resistance exercise in a protein fed state. The amino acid leucine is the most potent activator of mTORC1, and training in a protein-fed state may mean a lower dose of leucine of 1.2g (from 1.8-2g) is needed post-training to maximize the anabolic response (Reidy & Rasmussen, 2016; Witard et al., 2013). For example, training 3 hours after a meal containing 45g protein lead to a maximal stimulation of MPS with 1.2g leucine consumed in a protein dose post-workout (Witard et al., 2013). Maximal MPS stimulation has been observed with a meal containing 30g protein: the limiting factor is the quantity of essential amino acids [EAA], and 8-10g EAA’s will maximize the anabolic response (Symons et al., 2009; Atherton & Smyth, 2012).

Practically, this means that resistance training should optimally be performed in the fed state, with a meal containing 8-10g EAA’s (around 30g protein) consumed within the 3-hours prior to training (Witard et al., 2013). For early morning or fasted training, a branched-chain amino acid supplement containing at least 2,000mg leucine taken immediately before hand would suffice.

Timing Protein – Bro Myth no.2: you have to eat every 2 hours, bro!

See the graph below? The red line is MPS; the dotted black line is amino acid availaibility and mTOR stimulation.

What this is showing is a phenomenon termed “the muscle effect”, in which the MPS starts to decline even though there are still amino acids in circulation to stimulate the mTORC response i.e., the MPS response becomes resistant to continued stimulation by protein (Atherton et al., 2010; Atherton & Smith, 2012). In this graph, we’re looking at a resting response, where MPS has returned to baseline around 180 minutes after stimulation; the difference with resistance training, is that it can delay the “muscle full” response to protein intake for up to 24 hours post-workout (Atherton & Smith, 2012).

 

Figure 1
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The ‘muscle-full’ effect. Relationship between MPS, AA and intramuscular signalling (From Atherton & Smith, 2012).

Avoiding the “muscle full” effect was the genesis for the suggestion that lower doses of protein spread more evenly is optimal for those prized gainnz. In one study, feeding 20g every 3 hours elevated MPS greater than 40g every 6 hours or 10g every 90 minutes (Areta et al., 2013). This may be irrelevant, however, because of the effect of resistance training on delaying the muscle full effect for up to 24-hours after a workout (Atherton & Smith, 2012).

At this point, what appears to be the most important factor is total protein intake over a 24-hour period, not any specific timing of intake (Reidy & Rasmussen, 2016; Schoenfeld, Aragon & Kreider, 2013). The practicalities of getting in a certain total daily intake, however, would suggest having 3-4 protein meals spaced throughout the day (Schoenfeld, Aragon & Kreider, 2013).

Type of Protein – Bro Myth No.3: you need to get that hydrolyzed isolate polypeptide whey into you, bro!

Research looking at both whey (Witard et al., 2013) and egg (Moore et al., 2009) proteins led to the suggestion that these proteins were superior than other types, as they caused maximal stimulation of MPS at lower doses (20g) and were rapidly absorbed.

Other research comparing whey proteins against plant-based proteins saw whey emerge as superior, however, one vital piece of the picture was not being matched in these studies: the leucine content of the proteins being compared (Reidy & Rasmussen, 2016). A 20g dose of whey will deliver 1.8g of leucine, sufficient to maximally stimulate MPS, but comparing the equivalent dose of a plant-based protein wouldn’t be a fair comparison, due to its lower leucine content (Ibid.).

In fact, where leucine content is matched between different protein sources, the type of protein appears to be irrelevant for simulating MPS once a dose of 1.8-2g leucine is obtained (Ibid.). In this regard, doses of either 48g rice protein or 25g pea protein, which both provide 2g leucine, are equivalent to whey in stimulating MPS because the leucine threshold is achieved (Joy et al., 2013; Babault et al., 2015).

One aspect of bro protein folklore which does appear to have merit, is the idea of consuming casein protein, i.e. dairy protein, before bed. The slower digestion rate of casein stimulates MPS up to 6 hours post-workout, and diminishes the “muscle full effect” due to the slower rate of absorption and delivery of amino acids to circulation (Reitelseder et al., 2011). Consuming casein before bed can also maintain MPS throughout the night, during a period where no food can be ingested (Res et al., 2012).

Dose of Protein – Bro Myth No.4: you can only absorb 20g at one time, bro!

As we’ve seen, the idea that 20g was a maximal threshold was a reflection of the leucine content of the protein, and not the protein dose itself (Reidy & Rasmussen, 2016). The optimal dose, therefore, will be different depending on the source of protein. Rather than think in terms of an overall dose to maximize MPS, think in terms of thresholds for EAA’s and leucine, for which you want 8-10g EAA’s and 2g leucine (Babault et al., 2015).

So depending on your protein source, you might need less or more to get to that threshold; for example, 113g lean beef would get you 30g total protein and 8-10g EAA’s, but you’d need around 48g of a rice protein powder to hit the same threshold (Symons et al., 2009; Joy et al., 2013). There is an argument to be made for protein powder supplements, due to their easier and more rapid digestibility and absorption (Burke et al., 2012).

Remember, you don’t have to slam it down as soon as the bar is racked – around an hour post-workout and you’ll be fine (Schoenfeld, Aragon & Kreider, 2013). A lot of energy gets wasted into planning timing and distribution strategies, but as we noted, these appear to be largely irrelevant at this point: the paramount factor is your total daily intake of protein (Atherton & Smith, 2012; Schoenfeld, Aragon & Kreider, 2013).

Protein Daily Requirements – Bro Myth No.5: you need a gram per pound of bodyweight, bro!

The consensus at this point for strength athletes is to consume in the range of 1.2-1.8g per kg bodyweight (Phillips, 2012). This does depend on your energy status, however. For strength training athletes in a fat loss phase with an energy deficit, maintaining higher protein intake in the region of 1.8-2.7g per kg may be the most effective in preserving lean body mass (Phillips & Van Loon, 2011).

A prudent strategy for those continually engaged in resistance training, is to consume at the higher end of the spectrum, depending on energy status, in order to maintain positive protein balance (Schoenfeld, Aragon & Kreider, 2013; Lemon et al., 1992).

So, if eating at maintenance or in positive energy balance, 1.2g-1.8g per kg would be more than sufficient.

If in an energy deficit, 2-2.7g per kg may be more appropriate.

Summary Advice

So, what are some best practices to take from this?

  • total protein intake matters most:
    • If eating at maintenance or in positive energy balance, 1.2g-1.8g per kg would be more than sufficient (Phillips, 2012).
    • If in an energy deficit, 2-2.7g per kg may be more appropriate (Phillips & Van Loon, 2011).
  • eat a high protein meal (30-45g) in the 3 hours prior to training, which should contain 8-10g EAA’s (Witard et al., 2013);
  • consume a protein supplement containing 8-11g EAA’s and 2g leucine around an hour after training (Witard et al., 2013; Babault et al., 2015; Reidy & Rasmussen, 2016);
  • eat a casein-based protein source before bed for slower digestion (Res et al., 2012). Don’t sweat this if you’re dairy intolerant: simply consume fat with your protein before bed to slow gastric emptying and prolong digestion.

 

References:

Areta, J., Burke, L., Ross, M., Camera, D., West, D., Broad, E., Jeacocke, N., Moore, D., Stellingwerff, T., Phillips, S., Hawley, J. and Coffey, V. (2013). Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. The Journal of Physiology, 591(9), pp.2319-2331.

Atherton, P., Etheridge, T., Watt, P., Wilkinson, D., Selby, A., Rankin, D., Smith, K. and Rennie, M. (2010). Muscle full effect after oral protein: time-dependent concordance and discordance between human muscle protein synthesis and mTORC1 signaling. American Journal of Clinical Nutrition, 92(5), pp.1080-1088.

Atherton, P. and Smith, K. (2012). Muscle protein synthesis in response to nutrition and exercise. The Journal of Physiology, 590(5), pp.1049-1057.

Phillips, S. and Van Loon, L. (2011). Dietary protein for athletes: From requirements to optimum adaptation. Journal of Sports Sciences, 29(sup1), pp.S29-S38.

Babault, N., Paâzis, C., Deley, G., Guãcrin-Deremaux, L., Saniez, M., Lefranc-Millot, C. and Allaert, F. (2015). Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. J Int Soc Sports Nutr, 12(1), p.3.

Burd, N., West, D., Moore, D., Atherton, P., Staples, A., Prior, T., Tang, J., Rennie, M., Baker, S. and Phillips, S. (2011). Enhanced Amino Acid Sensitivity of Myofibrillar Protein Synthesis Persists for up to 24 h after Resistance Exercise in Young Men. Journal of Nutrition, 141(4), pp.568-573.

Burke, L., Winter, J., Cameron-Smith, D., Enslen, M., Farsfield, M. and Decombaz, J. (2012). Effect of intake of different dietary protein sources on plasma amino acid profiles at rest and after exercise. Int J Sport Nutr Exerc Metab, 22(6), pp.452-62.

Dreyer, H., Fujita, S., Cadenas, J., Chinkes, D., Volpi, E. and Rasmussen, B. (2006). Resistance exercise increases AMPK activity and reduces 4E-BP1 phosphorylation and protein synthesis in human skeletal muscle. The Journal of Physiology, 576(2), pp.613-624.

Joy, J., Lowery, R., Wilson, J., Purpura, M., De Souza, E., Wilson, S., Kalman, D., Dudeck, J. and Jäger, R. (2013). The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutrition Journal, 12(1), p.86.

Lemon, P., Tarnopolsky, M., MacDougall, J. and Atkinson, S. (1992). Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. J Appl Physiol, 73, pp.767-75.

Moore, D., Robinson, M., Fry, J., Tang, J., Glover, E., Wilkinson, S., Prior, T., Tarnopolsky, M. and Phillips, S. (2008). Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. American Journal of Clinical Nutrition, 89(1), pp.161-168.

Phillips, S. (2012). Dietary protein requirements and adaptive advantages in athletes. British Journal of Nutrition, 108(S2), pp.S158-S167.

Rasmussen, B., Tipton, K., Miller, S., Wolf, S. and Wolfe, R. (2000). An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise. J Appl Physiol, 88, pp.386-92.

Reidy, P. and Rasmussen, B. (2016). Role of Ingested Amino Acids and Protein in the Promotion of Resistance Exercise-Induced Muscle Protein Anabolism. Journal of Nutrition, 146(2), pp.155-183.

Reitelseder, S., Agergaard, J., Doessing, S., Helmark, I., Lund, P., Kristensen, N., Frystyk, J., Flyvbjerg, A., Schjerling, P., van Hall, G., Kjaer, M. and Holm, L. (2010). 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(1), pp.E231-E242.

Res, P., Groen, B., Pennings, B., Beelen, M., Wallis, G., Gijsen, A., Sended, J. and Van Loon, L. (2012). Protein Ingestion before Sleep Improves Postexercise Overnight Recovery. Medicine & Science in Sports & Exercise, 44(8), pp.1560-1569.

Schoenfeld, B., Aragon, A. and Krieger, J. (2013). The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. J Int Soc Sports Nutr, 10(1), p.53.

Symons, B., Sheffield-Moore, M., Wolfe, R. and Paddon-Jones, D. (2009). Moderating the portion size of a protein-rich meal improves anabolic efficiency in young and elderly. J Am Diet Assoc, 109(9), pp.1582-1586.

Witard, O., Jackman, S., Breen, L., Smith, K., Selby, A. and Tipton, K. (2013). Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. American Journal of Clinical Nutrition, 99(1), pp.86-95.