IMPLICATIONS OF PROTEIN CONSUMPTION BEFORE BEDTIME
The importance of protein consumption in generating adaptive muscle responses to training is widely known in the sports field. For this reason, many studies have been devoted to answering the questions that arise in this relationship between protein intake/maximal rates of protein synthesis: what type of protein is best? in what quantity? At what time of day? We will now answer these questions on the basis of scientific evidence.
EFFECT OF PROTEIN ON SPORTS PERFORMANCE
Consuming adequate amounts of dietary protein will:
- Inhibit muscle protein breakdown.
- stimulate muscle protein synthesis.
- facilitate the adaptive response of skeletal muscle to training.
In football, these effects favour the strengthening of muscle groups that contribute to improving physical qualities such as strength and power, which are essential for optimal sporting performance. Adequate protein intake also promotes increased satiety, leading to a reduction in overeating tendencies.
Daily protein intake for athletes should be in the range of 1.6 to 2.2 g/kg body weight (UEFA Consensus 2020). These recommendations are largely based on nitrogen balance studies vs. peak protein synthesis rates. However, it has been shown that higher intakes, in the range above 2- 2.4 g/kg body weight, better maintain muscle mass in the presence of energy deficit. The choice of the right amount of protein will depend on the individual goals for each player.
For the distribution of protein intake during the day, the current recommendation according to the ISSN (International Society of Sports Nutrition) is a uniform distribution of protein doses every 3 to 4 h, depending on the athlete’s routine. Recommendations on the effective protein dose have also been established:
- Main meals: maximum protein synthesis rates with doses of 20g (0.3-0.4g/kg).
- Recovery: immediately post-exercise doses of 20-25g.
- 1 or 2 hours before bedtime: 20-40g (0.5g/kg).
EFFECT OF DIFFERENT PROTEIN SOURCES
Differences in the response of muscle protein synthesis to the consumption of different protein sources can be attributed to the intervention of factors such as variability in the absorption and content of essential amino acids, with the content of the amino acid leucine being one of the most interesting due to its function as an independent activator of protein synthesis.
Taking these factors into account, the best sources of protein are:
|ANIMAL ORIGIN||Skinless chicken Fish Egg whiteCalfWheyWhey WheyCasein|
|VEGETAL ORIGIN (lower digestibility compared to animal sources)||Pulses Nuts Pseudocereals: quinoa Soya beans|
|HIGHER CONTENT OF ESSENTIAL AMINO ACIDS||WheyCaseinSoybean Egg protein|
(*) Both whey and casein are milk proteins, both have the highest amount of leucine compared to all other protein sources.
EFFECT OF PROTEIN INTAKE BEFORE BEDTIME
Studies on this effect arise as a result of the drop in muscle synthesis rates during nocturnal recovery and the researchers’ interest in ruling out whether it was due to the limited availability of plasma amino acids during the night.
The evolution of studies has led to the recommendation of a final protein intake before bedtime, as this will increase muscle protein synthesis rates during nocturnal recovery, thus increasing the window of opportunity to modulate muscle protein metabolism.
Most pre-sleep protein research uses casein (whey in second place). As mentioned above, both casein and whey are the main sources of quality protein due to their high content of essential amino acids, high leucine content and easy digestibility. However, the main difference between the two is the speed of absorption, with casein being slower, which allows it to be available for a longer period of time.
INPUTS ASSOCIATED WITH THE CONSUMPTION OF PROTEIN
In addition to knowing the benefit of this nocturnal feeding strategy, studies have ruled out problems that may be associated with it, which are discussed below:
- It may be less absorption taking into consideration that overnight human intestinal motility follows a circadian rhythm with reduced nocturnal activity
EVIDENCE: Both digestion and absorption occur properly, resulting in a continuous supply of amino acids derived from dietary protein into the circulation. Increased amino acid availability at night increased post-exercise muscle protein synthesis rates, thus improving total body protein balance at night.
- Could it reduce the appetite for the first intake in the morning?
EVIDENCE: Protein consumption before bedtime does not appear to reduce appetite at breakfast, nor during the day, and does not alter resting energy expenditure. When applied for prolonged periods in conjunction with strength training it is associated with a beneficial effect on muscle mass and strength gain.
- Could night-time protein consumption lead to an increase in body fat?
EVIDENCE: Data from men and women indicate that protein before sleep does not change fat metabolism during the night. It has been reported that research participants who consumed casein-based protein vs. a non-caloric placebo had no difference in nighttime fuel use or energy expenditure. It has thus been established that protein taken before sleep does not hinder fat metabolism and may even help improve body composition in the long term.
CONCLUSIONS ON PROTEIN CONSUMPTION
The main indication to support muscle development is to ensure an optimal intake of protein in quantity and quality throughout the day. Research has also shown a better utilisation with doses equivalent to 20g at each meal time and 20-24g immediately after exercise. However, the post-exercise increase in the rate of muscle protein synthesis is not maintained during the subsequent night’s sleep.
Recent work shows that protein consumed before sleep is effectively digested and absorbed during the night, thereby increasing plasma amino acid availability and stimulating post-exercise muscle protein growth during the night phase.
Thus, consumption of dietary protein before bedtime may represent an effective dietary strategy to inhibit muscle protein degradation, stimulate muscle protein synthesis, facilitate the adaptive response of skeletal muscle to exercise and improve training effectiveness especially in competitive times.