The same principles for the formation of muscle mass gain have been on repeat for decades now: “train, eat and sleep”
But… what does science say about it? What factors can get in the way of our goal of gaining muscle mass? What prevents the formation of muscle mass?
First and foremost, and this is indisputable, nutrition plays a fundamental role in variations in the muscle mass of individuals
In its gain, loss and maintenance.
Variables that control the loss of muscle mass
There are two fundamental aspects that we need to control to prevent the loss of muscle mass as a result of inadequate nutrition:
- Energy balance
- Protein intake
First of all, it’s important to highlight the dearth of scientific literature with samples that can be replicated by the general readership of this article. In terms of muscle mass loss and nutrition, most quality trials are performed on populations in which these measurements are of clinical interest: menopausal and/or postmenopausal women and the elderly.
Surplus, Normocaloric and Deficit
Let’s first look at the three scenarios in which we’ll find ourselves referring to calorie intake and its effect on muscle mass:
- A surplus leads us to gain muscle mass;
- An isocaloric diet (that is, when we consume the same amount of energy we use) will not make us gain muscle mass, except in specific cases; and
- A diet with a calorie deficit will cause us to lose muscle mass; and the amount of loss is conditioned by the magnitude of the caloric deficit.
How do you calculate the amount of calories you need a day?
Study on the effects of caloric deficits
This is what Sénéchal et al. (2012) found, who carried out an analysis of the effects of calorie deficit on 2 groups of postmenopausal obese women.
Figure I. Effects of Rapid WL vs Slow WL on body composition and metabolic risk factors. (Sénéchal et al. 2012)
The aim of the study was to reach a weight loss of 5% in the women. The sample was split into two groups, depending on the time determined to generate this loss (5 vs 15 weeks) and, therefore, the deficit needed (-1338 vs -465kcal).
As you can seen in the image, women in the fast weight loss group lost approximately the same amount of weight as those in the slow weight loss group; however, the source of that weight was different:
But most significant of all was the loss of 7.25 times more fat-free mass than the slow weight loss group (2.9 vs 0.4). There’s no analysis of the origin of that fat-free mass loss in the study (which can be muscle mass, bone mass, visceral, water…).
Therefore, the size of the calorie deficit greatly determines the amount of muscle mass lost. If you don’t want to lose the muscle mass you’ve gained, control your calorie deficit.
Protein intake to prevent loss of muscle mass
It should be noted that the nutrient distribution in this trial was seriously inadequate if the aim was not to lose muscle mass (55% Carbs, 30% Fat, 15% Prot).
On this point, there is no doubt that inadequate protein intake leads to an associated loss of muscle mass. However, there is a series lack of knowledge about the amount of protein needed to avoid these losses, not least because there’s no consensus on this issue.
Nevertheless, we should keep in mind that the current recommendations to maximise muscle protein synthesis is to consume 0.4-0.55g of protein/kg of body weight 4 times a day.
This number should be increased in specific populations that have anabolic resistance (such as the elderly), and people with large caloric deficits
This is shown by Bopp et al. (2013) in postmenopausal women, where they subjected the sample to a weight loss program, divided into 2 groups, of low and high protein consumption (0.47g vs 0.8g of protein/kg/day).
The authors reached a clear conclusion, namely that:
For each 0.1g of protein/kg weight/day increase in dietary protein intake, participants lose 0.62kg less fat-free mass (Bopp et al. 2013)
Figure II. Relationship between changes in the amount of lean mass (kg) (Y-axis) in relation to daily protein consumption (g/kg/day) (X-axis) (Bopp et al. 2013)
We need to keep in mind that both protein intakes are well below the recommendations to optimise MPS. However, 0.8g/kg/day is still the classic GDR.
A low protein intake is undoubtedly associated with a loss of muscle mass!
“Rest” is a broad term that groups a large number of factors relevant to the gain and/or loss of muscle mass. However, in this article, we’ll focus on the more classic aspect of rest: sleep.
As sleep is a complex organic process, we’ll not stop to explain the importance of the different latency periods of the sleep phases. Instead, we’re going to approach it from a very practical point of view with regards to our aim today.
Study on the quantity and quality of sleep
Firstly, there’s a study with a large sample of 10,125 Chinese students where the quantity and quality of sleep was related to performance in strength tests, which, despite not being a direct marker of muscle mass, is an indirect determinant of it.
The quality and recent publication of the study makes it worth including in this review. Chen et al. (2017) showed the following:
Figure III. Relationship between quality of sleep (poor, normal and good) and result in manual grip test (newtons) in men and women (Chen et al. 2017)
Those who had a good quality sleep were able to show around 2 Newtons more strength than those who had poor quality sleep. In women, the significance is not as high, but still the data seem robust.
Figure IV. Relationship between amount of sleep (<7, 7-8, >8 hours/day) and result in manual grip test (newtons) in men and women (Chen et al. 2017)
Hours of sleep or hours of quality sleep?
It’s common to hear people argue that even if you only sleep a few hours, if they’re quality hours of sleep, they’re enough…
After making clear the association between sleep quality and strength, Chen et al. (2017) showed that a variation as small as sleeping 7 hours or sleeping between 7 and 8 hours had a significant impact on muscle strength as expressed in the manual grip test.
Again, the data is significant in men and not so much in women, although there seems to be a slight variation that confirms the hypothesis.
The body of evidence linking sleep and muscle mass is poor and of poor quality
One possible explanation is provided by Leproult & Van Cauter (2011), where they subjected 10 healthy young men to a trial of resting conditions and partial sleep restriction to measure 24-hour serum testosterone and cortisol profiles.
The results are conclusive; adolescents suffered a decrease of between 10-15% in testosterone levels by restricting sleep from 10 to 5 hours a day.
Sleeping 5 hours a day is the reality for a lot of people looking to increase their muscle mass; so is staying up a little longer to eat one more meal more important than sleeping a little longer?
Figure V. Profile of serum concentrations of testosterone (left) and cortisol (right) under rest conditions (solid line) and partial sleep restriction (dashed line) for 24 hours. (Leproult & Van Cauter, 2011)
However, as the image shows, the serum cortisol profile, contrary to what the majority of the population believes, didn’t undergo significant variations after partial sleep restriction.
So if you want to avoid an unfavourable hormonal environment for maintaining muscle mass, sleep a lot and well.
Getting better quality sleep
Some sleeping supplements can help with this
The most relevant being melatonin. A neurohormone that controls sleep/wakefulness cycles in humans and animals and that is negatively conditioned by many behaviours we perform daily (consumption of stimulants, exposure to blue light emitted by electronic devices…).
First of all, as I explained in previous articles about sarcopenia and muscle memory, training is necessary for the creation of new mionuclei and to stimulate protein synthesis through the amplification of enzymatic processes aimed at recovering the damage produced in the muscle cell after training.
Without mechanical tension (which doesn’t always mean an external load), muscle tissue undergoes a period of atrophy
Training is necessary to maintain muscle mass
However, overtraining is often mentioned as a cause of muscle mass loss
Overtraining is a multifactorial clinical condition whose signs have not yet been clearly determined. Excessive muscle damage (as a more appropriate notion) can be a factor that conditions an anabolic/catabolic environment of musculoskeletal tissue.
The image below is a classic in any physiology class, and it explains it well:
Figure VI. Cellular states (normal, reversible damage, and irreversible damage). Source: https://slideplayer.com/slide/8937201/
Without stimulus, the cell is in a basal (“normal”) state, and through training we damage the myocyte, which causes it to suffer a reversible injury, where the cell undergoes a “swelling” process and a series of organic processes are triggered to repair it (leukocytes, macrophages, satellite cells, myokines, EROS…).
However, if we follow a training plan that’s too demanding for our capacity, we can produce irreversible damage to the cell, compromising the integrity of the phospholipid membrane and the cell nucleus(es) and degenerating into cell necrosis, i.e. losing a muscle cell.
When you suffer stiffness for 7 days after a leg workout or urinate cola (rhabdomyolysis), then you can talk about overtraining…
- Leproult, R., & Van Cauter, E. (2011). Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA, 305(21), 2173–2174. https://doi.org/10.1001/jama.2011.710
- Senechal, M., Arguin, H., Bouchard, D. R., Carpentier, A. C., Ardilouze, J.-L., Dionne, I. J., & Brochu, M. (2012). Effects of rapid or slow weight loss on body composition and metabolic risk factors in obese postmenopausal women. A pilot study. Appetite, 58(3), 831–834. https://doi.org/10.1016/j.appet.2012.01.014
- Bopp, M. J., Houston, D. K., Lenchik, L., Easter, L., Kritchevsky, S. B., & Nicklas, B. J. (2008). Lean mass loss is associated with low protein intake during dietary-induced weight loss in postmenopausal women. Journal of the American Dietetic Association, 108(7), 1216–1220. https://doi.org/10.1016/j.jada.2008.04.017
- Knowles, O. E., Drinkwater, E. J., Urwin, C. S., Lamon, S., & Aisbett, B. (2018). Inadequate sleep and muscle strength: Implications for resistance training. Journal of Science and Medicine in Sport, 21(9), 959–968. https://doi.org/10.1016/j.jsams.2018.01.012
- Chen, Y., Cui, Y., Chen, S., & Wu, Z. (2017). Relationship between sleep and muscle strength among Chinese university students: a cross-sectional study. Journal of Musculoskeletal & Neuronal Interactions, 17(4), 327–333.
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