Does protein distribution matter for maximising your muscle gains?

How much protein can you utilise at once? And is it okay to eat all of your protein in one sitting?

Table of contents:

• Debunking misconceptions
• What quantity of protein maximises MPS
• What does the research say on protein distribution and mass gains?
• So does protein distribution matter?
• How much protein per meal?
• Other factors that influence MPS
• Takeaways

Debunking misconceptions

Common misconception: there is a “limit” to how much protein can be absorbed by the body.

The term absorption refers to the nutrients that can be absorbed from the gut into the blood stream and by this definition, it is virtually unlimited!

So what do people mean when they refer to this idea of “protein absorption limits”?

Likely, how much protein can maximally stimulate muscle protein synthesis (MPS). This is known as the muscle full concept – that anything above a certain quantity of protein consumed will either be utilised to generate energy (oxidised) or changed into another substance for the body to use.

Studies indicate that if you infuse a muscle with amino acids (AAs- the building blocks of protein), there is a short delay (approx. 45 mins) before MPS approximately trebles (between 30-120 mins) after which it returns to baseline, despite elevated availability of AAs (1,2).

What quantity of protein maximises MPS?

Initial research indicated that 20g of whey protein maximised MPS in men following resistance exercise (3). However a more recent study showed that a 40g dose of whey protein increased the rate of MPS by 20% versus a dose of 20g of whey (4).

However since building muscle is a balance between MPS and muscle protein breakdown (MPB), we must also consider the  impact of protein quantity on MPB. A comparison of the consumption of either 40g or 70g beef protein showed the higher protein intake to promote a significantly greater whole-body anabolic response, primarily due to a reduction in MPB (5).

However, a limitation of this study is that it measured protein balance at the whole-body level. The capacity to assimilate dietary protein at a whole body level is substantially greater than for muscle tissue and it would seem more likely that these AA would have been utilised for tissues such as the gut.

What does the research say on protein distribution and mass gains?

Although there is research to indicate a maximum quantity of protein can be utilised in one window of feeding to maximise MPS, research to show how this translates into lean muscle mass change is limited.

Research that challenge the notion that protein distribution does not matter:

• A 14-day study showed that consuming the majority of protein intake (79%) in one single meal resulted in a greater retention in fat-free mass (FFM) than distributing protein over four meals (6)
• A systematic review on intermittent fasting (IF) also concluded that IF has similar effects on FFM to continuous eating (7)
• An 8-week trial by Moro et al. (8) on resistance trained individuals following a calorie matched diet found that the time restricted feeding (TRF) group (16:8) retained equal amounts of lean body mass as the regular group – despite losing fat mass.

However, there are several limitations to this research. These include, the short durations over which the studies were conducted, the use of BIA (bioelectrical impedance analysis) to measure body composition and importantly comparisons of overall low total protein intake.

Since total protein intake is the most important factor for maximising mass gains, comparing protein distributions where individuals are meeting their optimal protein intake would be necessary in order to draw meaningful conclusions.

Studies indicating that protein distribution does matter:

• A study comparing a meal intake of 3 versus 6 meals (protein 2.27 and 2.15 g/kg bodyweight) found that the 6 meal group gained a significant greater amount of lean body mass (9)
• Another couple of studies also show that the repeated ingestion of 20g of whey protein (0.25 g/kg) at 3 hour intervals supports the greatest rates of MPS and whole net protein balance over 12 hours following a resistance exercise session (10,11).

So does protein distribution matter?

Limitations to utilising current research on protein distribution are the comparison of different amounts of protein distributed per day and total protein intakes, over differing time frames. Additionally, short-term conclusions are not necessarily translatable into the long-term.

However, studies do consistently show that the dosing ceilings for maximising MPS may be between 0.4 – 0.6 g/kg (3,4), indicating that distributing protein is pertinent when maximising MPS (it should be noted that this is based on a rapidly digesting protein source).

Additionally studies support distributing protein into 4-5 meals per day for athletes, concluding that this feeding frequency may be most favourable and metabolically efficient when the goal is to maximise mass gains and minimise the oxidation of AA (10,11).

How much protein per meal?

Prioritise evenly distributing total protein intake between number of meals per day to maximise muscle strength and size. A recent meta-analysis of studies indicated that regardless of being in an energy balance or energy excess, 1.6-2.4 g/ kg/day may be beneficial (12).

When having 4 meals per day 0.4–0.6 g/kg/meal would facilitate meeting protein requirements of 1.6-2.4 g/kg/day (12).

Whether you shoot for a slightly higher or lower amount may be decided based on your individual needs, protein source and how well you digest the protein – go for the lower end of the scale if you are overweight and higher end if you are leaner and train more.

Whilst higher protein consumption may result in AA oxidation, research indicates that additional protein may be utilised for tissue building purposes.  

Other factors that may impact MPS rates:

Protein source: you want the optimal ratio of EAAs (essential amino acids) and leucine – animal sources of protein such as whey or egg have these.

Quality of protein: a protein that has the optimal ratio of EAAs and leucine and is easily digested may have very different effects to one that does not. Mixed protein blends, with lower quantities of EAAs and leucine, which are less well digested, generally result in a suboptimal MPS response compared to an equal amount of whey protein (15).

Therefore when consuming plant based proteins you will require a larger quantity to have the same impact.

Whether the food is whole: whole food sources may have a more anabolic effect. For example, whole milk may be more anabolic than skimmed milk and whole eggs more so than egg white (16,17).

Being in a negative energy balance: during chronic dieting, or due to low energy availability (being very lean or as an athlete) the protein intake required to maximise MPS may be slightly greater (19,20).

Shooting for the higher intake of protein per meal (0.5 g/kg/meal) is recommended. A higher protein intake is also beneficial for individuals needing to cut or lose weight due to the benefits of feeling more full and post-prandial thermogenesis (increased energy expenditure!).

Age: research indicates that for individuals >70 years, the ingestion of 40g of whey enhanced post-exercise MPS to a greater extent than 20g of whey (14).

Takeaways:

Prioritising hitting your daily protein intake is the most important nutrition factor for maximising your gains: so hitting 1.6-2.4 g/kg protein/bodyweight per day. This is your priority.

Distributing protein between 4 meals may be optimal: with research indicating a cap of 0.4-0.5 g/kg of protein to maximise MPS.

Consider your protein source: and adjust the quantity based on the quality and how well you digest it. If you are consuming plant based protein it is likely that you will require a higher total intake. Additionally a whole-foods source may be slower digested than a whey protein so consider this with timing around your training.

Related articles:

The importance of protein and its benefits

Nutrient timing – what’s the deal and does it matter when you eat?

What and when to eat for muscle gains?

What are your thoughts on protein distribution? Is it something that you prioritise? Would love to hear in the comments below!

References:

1. Bohe et al. (2001). Latency and duration of stimulation of human muscle protein synthesis during continuous infusion of amino acids.
2. Atherton et al. (2010). Muscle full effect after oral protein: time-dependent concordance and discordance between human muscle protein synthesis and mTORC1 signalling.
3. Moore et al. (2009). Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men.
4. Macnaughton et al. (2016). The response of muscle protein synthesis following whole-body resistance exercise is greater following 40g than 20g of ingested whey protein.
5. Kim et al. (2016). The anabolic response to a meal containing different amounts of protein is not limited by the maximal stimulation of protein synthesis in healthy young men.
6. Arnal et al. (2000). Protein feeding pattern does not affect protein retention in young women.
7. Seimon et al. (2015). Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials.
8. Moro et al. (2016). Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males.
9. Arciero et al. (2013). Increased protein intake and meal frequency reduces abdominal fat during energy balance and energy deficit.
10. Areta et al. (2013). Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis
11. Moore et al. (2012). Daytime pattern of post-exercise protein intake affects whole-body protein turnover in resistance-trained males.
12. Morton et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults.
13. Moore (2019). Maximising post-exercise anabolism: the case for relative protein intakes.
14. Yang et al. (2012). Resistance exercise enhances myofibrillar protein synthesis with graded intakes of whey protein in older men.
15. Tang et al. (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.
16. Elliot et al. (2006). Milk ingestion stimulates net muscle protein synthesis following resistance exercise.
17. Van Vliet et al. (2017). Consumption of whole eggs promotes greater stimulation of postexercise muscle protein synthesis than consumption of isonitrogenous amounts of egg whites in young men.
18. Millward et al. (1998). Metabolic demands for amino acids and the human dietary requirement.
19. Hector et al. (2018). Pronounced energy restrictions with elevated protein intake results in no change in proteolysis and reductions in skeletal muscle protein synthesis that are mitigated by resistance exercise.
20. Longland et al. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomised trial.