Protein Timing

Does protein timing matter? If so, how much of a difference does it make? Understanding performance and health parameters for protein timing may offer some slight improvements otherwise lost. In this article, we will investigate what the research says on protein timing, quantity of protein, and even touch on the quality of protein to take.

Protein Intake – What is Optimal?

This question is incredibly difficult to answer at the moment, because the research has a lot of holes that need to be bridged. Although there are several studies that look into protein timing on full body protein synthesis [7][10], and there are several that looked at muscle protein synthesis [1][2][3][4][6][8], but all of these studies are all over the place in their results and conclusions. So, where do we go from here?

Its hard to say, but the answer may still lie in the quagmire.

Differences in subjects, protein amounts, number of subjects, activity level, and other factors all create a serious issue when trying to come to a conclusion, so I reserve the right to change my perspective in light of new research (granted, I always reserve that right as a science based learner – so should you!).

Protein timing seems to be mainly different between two types of people, young and elderly. Young being defined as anyone under 35, and elderly being defined as anyone over 50-55 [1][2].

Younger Population

First off, everyone needs to consume enough protein, in total. Studies that show inadequate protein ingestion tend to show a greater reliance on timing, with even distribution of protein every 3-4 hours being superior to bulk intake in 1-2 meals [1]. However, assuming you are consuming adequate protein for inactive individuals, distribution may not matter much in stimulating protein synthesis [3][7]. In active individuals, protein distribution may matter more as a person may not only need to initially take advantage of a rather wide “window of opportunity” post workout, but continue to maximize benefits by sustaining maximum protein synthesis rates for as long as possible [8].

Younger populations can stimulate muscular (and body) protein synthesis by consuming quality protein containing highest levels of leucine (ex. Whey protein) as leucine is the driving amino acid for protein synthesis [12][13]. Not only that, to nearly maximize protein synthesis, a person should consume 20-25g of protein every 3-4 hours (more exactly stated, 0.24g/kg of BW); consuming 30 or 40g of leucine rich protein will only further increase protein synthesis by 10%, so the effect does have diminishing returns – not to mention there is a point at which protein oxidation will increase [4][11][12][20].

[12]
Elderly
Population

Elderly populations, things change a bit. For a person in a more advanced age, the rules shift, and the research is less conclusive on distributed intake or more concentrated intake. Some research shows benefits of concentrated intake limited to 1 meal of high protein and 1 meal of low protein is superior to 4 meals containing protein [10]. This research throws a wrench in our understanding, especially as other research indicates protein synthesis is about the same between even distribution and concentrated intake [2]. These differences may be due to an investigation of full body vs muscle synthesis, but as we do not know, there is a bit of an unknown element. However, there are some things of which we are certain, like the necessity for leucine, just like in younger populations, and an increased need for protein per meal to maximize protein synthesis [4]. So, elderly populations should consume double that of younger populations, with protein intake, per meal, set around 40g, possibly even higher [4].

Sleep

Now, while we understand that protein evenly distributed trends toward the correct practice at slightly improving protein synthesis rates, this is all well and good when you are awake, but what about when you are asleep?

This is an interesting addition to the story, because although the intestinal tract modulates its activity differently between waking and sleep, with deep sleep stopping intestinal movement and other stages of sleep allowing intestinal contractions to occur, there is still an effect of protein on protein synthesis that needs to be discussed [16][17]. One might imagine that it might be beneficial to consume 20-25g of leucine rich protein right before bed to continue this anabolic response overnight, and you’d be right and wrong.

[16]

According to the research, more protein is needed – roughly 40g or more [14][15][16]. Not only that, although whey is the protein with the highest leucine concentration, and therefore the best at producing a protein synthesis response, it is also a fast digesting protein, even in a sleeping individual, relatively speaking. So, while it has not been determined if whey is a suitable protein for sleep, it seems casein protein may have an edge – not because it produces a greater anabolic response (its leucine content is lower), but because it can sustain an anabolic response during sleep [14][15][16][18]. So, the current literature shows a need for 40g, maybe more, of casein protein prior to bed to see a continual protein synthetic response [14][16]. This practice has been shown to increase muscle mass by a small margin (~10%) [15].

Understanding the Physiology

The physiology is actually rather simple for those in the younger category.

Protein ingestion, up to a point, leads to increased available serum leucine, which is taken in by the cells and stimulate protein synthesis cascades. However, more is not always better as there is a point of diminishing returns. As previously mentioned, 20-25 grams of leucine rich protein will get close to saturating the muscle cells (and other cells) with leucine and other necessary amino acids to build more proteins, and increasing that to about 40g will just about cap out the final 10% boost. However, more protein (or continuous protein every few minutes) doesn’t do much more, due to the Muscle Full Effect, which describes that even if amino acids are still elevated and available, the cell will reduce protein synthesis after about 120 minutes of elevation via sensory mechanisms that are not readily understood, but certainly play a role on transcription and/or translation [5][6].

This increase in amino acids in serum, when they stimulate protein synthesis, also tend to knock down proteolysis (protein breakdown), so the two way effect has a compounding impact on protein accretion [20].

All of the above is true for elderly individuals, as well, but since their anabolic sensitivity tends to be lower, they need greater anabolic signaling (via leucine and overall protein) to see similar protein accretion. This reduced anabolic signaling is usually seen in inactive elderly populations as it is typically attributed to decreased phosphorylation (activation) of the mTOR signaling pathway [19][21][22]. However, other theories have been presented surrounding lower absorption of dietary protein and decreased microvasculature to the tissue – both reversible by physical activity [19]. Whichever the answer is still unknown, but for these reasons and more, increased protein is required to offset some of these issues.

As for the advantage of several feedings is in the realization that only a certain amount of protein per meal will maximize synthesis and decrease breakdown, so consuming protein semi regularly (but not so much so that amino acids stay high indefinitely), will create a “pulse on-off” system that falls in the sweet spot of protein synthesis stimulation as often as possible, holding protein breakdown as low as possible while maintaining synthesis as high as possible. This means that too many feedings may be detrimental and too few may, as well, but for opposite reasons.

Protein feeding at night is relatively self-explanatory, with a slow digesting, slow activating protein potentially being better as a person can see a slow (maybe not maximal, but higher than baseline) rise in synthesis while sleeping – again dropping protein breakdown and elevating growth.

SUMMARY

Protein timing matters, a little. It helps the most to consume 20-25g of leucine rich protein every 3-4 hours (30-40g for people over 50) with the overall goal of total protein in a day being the most influential to successful health and performance. Pre-bed time, it may be beneficial to consume around 40g of protein, preferably casein protein.

Author: Nicolas Verhoeven
References
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