Protein Intake: What We Know
The three major factors regulating muscle protein net balance and muscle protein synthesis are:
- Quantity of protein
- Quality of protein
- Timing of protein
Science has pretty much got factors one and two nailed down.
As far as quantity, the current, best research we have suggests that the optimum amount of protein for strength athletes is approximately 1.6 grams per kilogram of body weight per day.
Regarding protein quality, the current, best research shows that milk protein concentrate (casein) is the highest-quality protein, followed by whey protein concentrate and whey protein isolate with respective Digestible Indispensable Amino Acid Scores (DIASS) of 141, 133, and 125. (To offer a comparison, pea protein has a relatively anemic score of 73.)
As far as the third factor, protein timing, scientists are still trying to synchronize their watches in this important area. Instinctually, we've always thought that muscle growth is best served by a relatively even protein intake throughout the day, but a recent Japanese study indicated just how true that was.
The researchers found that eating disproportionate amounts of protein at breakfast and lunch, but especially breakfast, adversely affected muscle protein synthesis, regardless of total daily protein intake.
Specifically, a group of subjects fed a high-protein breakfast put on over 40% MORE muscle than a group of subjects fed a low-protein breakfast, even though both groups ingested the same amount of total daily protein.
But even among those people who do a pretty good job of keeping their protein intake equally proportionate and consistent throughout the day, most go through a protein "fast" every time they go to sleep. If, say, they have their last meal at the relatively late hour of 8 PM, they're likely to go without any dietary protein for 8 to 10 or even 12 hours.
A common recommendation is to ingest some protein just before going to bed, but just how important is this practice to muscle protein synthesis? A recently published meta-study addressed exactly that topic and found that it's a beddy-bye habit every strength athlete should adopt, no less important than brushing their teeth or putting on their sleep jammies.
In case you're not familiar with "meta" studies, they're in effect statistical analyses of multiple studies on the same topic. As such, they often point to truths or fallacies a lot more emphatically than a single study might.
This particular meta-study analyzed nine articles related to nighttime protein consumption effects on muscle protein synthesis. Here, in their own words, is what they concluded:
"The consumption of 20-40 grams of casein approximately 30 minutes before sleep stimulates whole-body protein synthesis rates over a subsequent overnight period in young and elderly men (preceded or not by resistance exercise, respectively).
In addition, pre-sleep protein consumption can augment the muscle adaptive response (muscle fiber cross-sectional area, strength, and muscle mass) during 10-12 weeks of resistance training in young, but not in elderly men."
The researchers even cited a broad survey of athletes conducted between 1999 and 2002. They found "greater leg lean mass and knee extensor strength in those consuming higher amounts of protein (20-30g) in the evening than those who consumed protein in the afternoon."
Also of interest, but maybe not a surprise, was that pre-sleep protein didn't do much of anything for endurance athletes.
Ingesting some protein at bedtime is advice we've all probably heard and practiced at some point in our lifting careers, but most of us just plain gave it up at some point. Either we dismiss its importance, or we worry that a protein drink will cause us to get up in the middle of the night to take a leak.
If your excuse is the former, this article should convince you otherwise – it's definitely important. If your excuse is the latter, fair enough, but you don't need to mix your protein in Big-Gulp quantities of liquid. A scoop or two of high-quality protein powder like Metabolic Drive® that isn't jammed full of thickeners will easily mix up in just three or four ounces of liquid, hardly enough to inflate your sleepy-time bladder.
Alternately, you could ingest a whole-food source of protein. While it may not be exactly as efficacious as a protein drink because it'll take extra time to digest, it's better than nothing.
- Reis CEG et al. Effects of pre-sleep protein consumption on muscle-related outcomes – A systematic review. J Sci Med Sport. 2021 Feb;24(2):177-182. PubMed.
- Buckner Sl et al. Protein timing during the day and its relevance for muscle strength and lean mass. Clin Physiol Funct Imaging. 2018 Mar;38(2):332-337. PubMed.