Proteins before sleep for more strength and muscle mass. Virtually every strength athlete does it based on bro science. Now it’s time to really investigate. I also look at the type of protein before going to sleep. For example, does it make sense to buy a (expensive) mix of proteins for so-called “time release”?
Bro Science
When I started my own fitness and bodybuilding blog about six years ago, I did it to share knowledge. However, with the first article, I realized that much of the “knowledge” I thought I had was nothing more than the adopted “knowledge” of others from the gym and well-known bodybuilders, Bro Science in other words. With everything I wanted to write, I realized that I actually didn’t know what that knowledge was based on. I completed a fitness instructor training and still felt I knew too little. At that moment, I decided to write all my articles on nutrition and training as investigative journalists. So first do thorough research on a certain topic and then write, with proper citations. In some cases, it confirms what you previously thought, while in other cases, you come to remarkable insights. In hindsight, this is also the only way to truly address a topic.
That seems very logical, in terms of content. However, commercially, many other bloggers have found that it works much faster if you just shout out what you think without substantiating it. That way, you can write many more articles and score faster. Others are even easier by simply copying entire texts with a few adjustments here and there. Why do research when someone else has already done it for you? I regularly come across articles that I spent weeks on that have been rewritten in an hour. Shameless, nothing compared to The Volkskrant.
One of the “gym wisdoms” repeated by thousands worldwide is that you should consume slow proteins before sleep to limit muscle breakdown and promote muscle growth. Let’s take that statement out of the Bro Science corner and apply some science to it. Time to see what the research says about this.
Slow protein and fast protein
Building muscle through training only works if protein synthesis, the production of proteins in the muscles, is greater than the breakdown of proteins in the muscles [1]. We then speak of a “positive net protein balance”. Limiting muscle breakdown is therefore just as important as promoting muscle growth.
When we talk about “fast” or “slow” proteins, we are referring to the speed at which the amino acids from the proteins are absorbed into the blood (protein is a chain of amino acids). On the one hand, it concerns the amino acids that reach the muscles via the blood, where they can work as building blocks to promote muscle growth. On the other hand, just the presence of amino acids in the blood reduces the need to break down protein in the muscles into amino acids (for energy).
Various studies have shown that the amino acids from, for example, whey protein enter the blood faster than those from casein. In a ridiculously long article (over 8000 words, 50 studies), I once delved into an even faster form of protein, namely hydrolysate [2]. Why is this speed important?
The simple explanation is that you want fast protein when the need/urgency is high, such as right after a workout or in the morning when your body hasn’t received anything for a long time. Slow protein is useful when you need protein for a longer period, such as before sleeping.
“Syntha-6? Waste of money”
The graph on the right is from a previous article where I compared the effects of whey and casein [3]. In this study, French researchers showed that the amino acids from whey (in this case, leucine was measured) are absorbed faster than the leucine from casein [4].
In a follow-up study, they concluded that this leads to whey providing a short-term (about 90 minutes) increase in protein synthesis, while casein limits breakdown for a much longer period (about 7 hours) [5].
If you look closely at this graph, you can see that casein provides a fairly constant increase in leucine from about 45 minutes after intake until 7 hours later. There are protein shake manufacturers that mix six different types of protein. One well-known one is, of course, Syntha-6 from BSN. The idea behind this is that each protein releases its amino acids into the blood at a different time to ensure that this supply remains stable (so-called “time release”). In a graph, you would then see six “waves” each with their peak at a different time. Take another look at the graph: How stable do you want it? At most, you could mix it with whey or a faster protein to avoid waiting 45 minutes. However, this assumes that your body/blood is deficient in amino acids for those 45 minutes. If, however, you eat a meal every two to three hours that also contains protein (like most bodybuilders do), you still have amino acids from the previous meal in your blood. So, in terms of absorption rate, there is no reason to take six different types of protein.
In any case, the French have nicely demonstrated that casein is indeed slow to be absorbed. It is strange, however, that this was only an assumption until 2012.
Casein before sleep for more strength and muscle mass: The research
2012 was actually the first year that this was tested. Maastricht University examined what happens to muscle protein synthesis after consuming 40 grams of casein half an hour before bedtime [6]. They found that protein synthesis was greater in the group that had taken casein than in the placebo group.
During sleep, casein protein was effectively digested and absorbed resulting in a rapid rise in circulating amino acid levels, which were sustained throughout the remainder of the night. Protein ingestion before sleep increased whole-body protein synthesis rates (311 ± 8 vs 246 ± 9 μmol·kg per 7.5 h) and improved net protein balance (61 ± 5 vs -11 ± 6 μmol·kg per 7.5 h) in the PRO vs the PLA experiment.
-P.T. Res, Maastricht University
(PRO = protein group, PLA=placebo group)
The net protein balance mentioned is the previously mentioned ratio between protein breakdown and synthesis.
Just this year, they looked again at the effects of casein before sleep, but this time at the effect on athletic performance [7].
Muscle strength increased after resistance exercise training to a significantly greater extent in the protein-supplemented (PRO) group than in the placebo-supplemented (PLA) group (+164 ± 11 kg and +130 ± 9 kg, respectively; P < 0.001). In addition, quadriceps muscle cross-sectional area increased in both groups over time (P < 0.001), with a greater increase in the PRO group than in the PLA group (+8.4 ± 1.1 cm(2) vs. +4.8 ± 0.8 cm(2), respectively; P < 0.05). Both type I and type II muscle fiber size increased after exercise training (P < 0.001), with a greater increase in type II muscle fiber size in the PRO group (+2319 ± 368 μm(2)) than in the PLA group (+1017 ± 353 μm(2); P < 0.05).
-T. Snijders, Maastricht University
They found that strength increased more, quadriceps became larger, and this increase was caused by a greater increase in the size of type I and II muscle fibers (the muscle fibers primarily used at higher intensity). In this case, 27.5 grams of casein were mixed with 15 grams of carbohydrates.
Casein before sleep the best?
We’re almost there. “We” have shown that casein is indeed absorbed slower and more gradually than whey. From this, we concluded that casein is more suitable for sleeping. Finally, we have also demonstrated that casein before sleep does indeed offer positive effects. However, we’re not yet sure if these are greater than if we were to take whey, as logical as this may seem. After all, we haven’t compared taking casein before sleep with taking whey before sleep.
Researchers from Florida State University did compare the effects of taking whey, casein, or carbohydrates before sleep last year [8]. Unfortunately, however, they did not look at the effect on protein synthesis and breakdown, but only at the effect on morning hunger and metabolism. They were more interested in the possible influence on obesity in people who often eat late. They saw no difference, but also only looked in the short term. However, they refer to other research (again from the French) showing that casein raises insulin levels less than whey [9]. This could mean that there is less fat storage when taken before sleep.
Unanswered questions
If we could establish that casein is indeed “the winner,” we would want to know what the ideal dosage would be. In one study from Maastricht, 40 grams of casein was used, while in another, 27.5 was combined with carbohydrates. The latter may make sense because glucose in the blood is needed for protein synthesis, although this may already be the case due to previous meals containing carbohydrates. Others may be concerned that this will increase insulin levels and lead to fat storage, but research on this is inconclusive.
We also need to consider what the ideal timing is, if such a thing exists. Half an hour before sleep as in the first study from Maastricht may be useful because we have seen that it takes about 45 minutes for the amino acids from casein to reach the blood. As mentioned, this can also be solved with an earlier meal. Personally, I would also be afraid that I would have to get up half an hour earlier to urinate, but more on that in a separate article.
Conclusion:
- Casein is indeed absorbed slower than whey.
- As a result, it limits muscle breakdown for a long time while whey briefly promotes muscle growth.
- Because casein provides a stable release of amino acids for up to 7 hours, a combination of a large number of different types of protein is not necessary at night.
- Research has shown that casein before sleep does indeed lead to a greater positive “net protein balance”.
- A direct comparison between the effects of whey vs. casein for sleep on muscle growth has unfortunately not been conducted yet. However, it does not seem like a strange assumption that the effects of casein will be greater.
- More insight is needed regarding dosage, combining with other macros like carbohydrates and fats, but also timing.
References
- Tipton KD, Wolfe RR. Exercise, protein metabolism, and muscle growth. Int J Sport Nutr Exerc Metab. 2001 Mar;11(1):109-32. Review. PubMed PMID: 11255140
- fitsociety.nl/eiwitshakes/peptopro-ervaring-en-review/
- fitsociety.nl/caseine/whey-of-caseine/
- YVES BOIRIE, MARTIAL DANGIN, PIERRE GACHON, MARIE-PAULE VASSON, JEAN-LOUIS MAUBOIS,AND BERNARD BEAUFRERE. Slow and fast dietary proteins differently modulate postprandial protein accretion. Proc. Natl. Acad. Sci. USA. Vol. 94, pp. 14930–14935, December 1997. Physiology
- Dangin M, Boirie Y, Garcia-Rodenas C, Gachon P, Fauquant J, Callier P, Ballèvre O, Beaufrère B. The digestion rate of protein is an independent regulating factor of postprandial protein retention.Am J Physiol Endocrinol Metab.
- Res PT, Groen B, Pennings B, Beelen M, Wallis GA, Gijsen AP, Senden JM, VAN Loon LJ. Protein ingestion before sleep improves postexercise overnight recovery. Med Sci Sports Exerc. 2012 Aug;44(8):1560-9. doi: 10.1249/MSS.0b013e31824cc363.PubMed PMID: 22330017.
- Snijders T, Res PT, Smeets JS, van Vliet S, van Kranenburg J, Maase K, Kies AK, Verdijk LB, van Loon LJ. Protein Ingestion before Sleep Increases Muscle Mass and Strength Gains during Prolonged Resistance-Type Exercise Training in Healthy Young Men. J Nutr. 2015 Jun;145(6):1178-84. doi: 0.3945/jn.114.208371. Epub 2015 Apr 29. PubMed PMID: 25926415.
- Night-time consumption of protein or carbohydrate results in increased morning resting energy expenditure in active college-aged men. Madzima TA, Panton LB, Fretti SK, Kinsey AW, Ormsbee MJ Br J Nutr. 2014 Jan 14; 111(1):71-7.
- Pennings B, Boirie Y, Senden JM, et al. (2011) Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men. Am J Clin Nutr 93, 997–1005.
