The times when adepts of strength sports were afraid of misdemaining with a meal outside the anabolic window are slowly passing by. Despite the change in the bodybuilding trend, the post-workout supply of amino acids is still very important. However, the question arises, what amount of protein is appropriate to achieve the maximum benefit?
It turns out that there is no equal answer for everyone. Analyzing scientific reports, we notice that the amount of protein required after training depends on various factors.
The most popular training diagrams are split, which is the division of different muscle groups into separate training sessions, and a full-body workout, involving the involvement of all parties on each training. Most of the research to check different amounts of protein on the level of muscle protein synthesis involves determining one resistance exercise or 2-3 exercises for one muscle lot. In such studies, it was noted that a dose of 40 g of egg or whey protein does not give significantly better results than the dose by half the amount, that is 20 g  .
Slightly different results were noted in the study in which a scheme more similar to FBW was chosen as the training model . 30 men were trained for the trial (at least 2 trainings a week for the last 6 months) and divided into two groups, with low and high lean body mass. Each of them approached the test twice to check the effectiveness of 20 and 40 g of protein supplement.
The course of the study looked as follows: the participants were standing on the spot, after which a cannula was installed in their veins. After the procedure the first blood sample was taken and then a standardized meal was given – 7 kcal per kg body weight, with 50% energy from carbohydrates, 30% from protein and 20% from fat. After breakfast, the participants were allowed to rest for two hours in a semi-sitting position, after which an infusion of isotope-labeled phenylalanine was connected, which was necessary to measure the level of protein synthesis.
Due to the need for frequent blood sampling during the infusion, another venous tube was installed in each participant. An additional blood sample was taken one hour after the infusion was started and strength training started. The following exercises were performed one after the other: squeezing lying down, paddling, bending legs, pushing legs and straightening legs with a 75% 1RM weight. Three sets with ten repetitions were performed, and the fourth with a muscle fall. Immediately after the training, a muscle biopsy was performed followed by a protein shake and a blood sample was taken. The diagram of subsequent downloads and biopsies can be seen in the below illustration. The entire process was completed after 300 minutes from the end of the training and then the infusion was also completed.
When designing the study, it was hypothesised that people with more lean body mass would need more protein for optimal stimulation of muscle protein synthesis, which would seem logical. In effect, it was noted that a 40 g serving of protein supplement gives better results than 20 g of conditioner. However, no significant differences in efficiency between groups with different levels of lean mass were noticed, which contradicted the initial assumptions.
To sum up, if we want to enjoy the maximum threshold for muscle protein synthesis, we should adjust the amount of post-workout protein we eat to the amount of muscles we train for work. As you can see in the study, this factor is more important than the weight of the person training. In the case of a classic split, in which we exercise only one or two muscle parties on one session, even 20-25 g of full-value protein should be sufficient. When we train the whole body, the demand for protein increases and the optimal amount is 40 g.
Of course, this is not the only exponent of the amount of protein consumed after training, because it also depends largely on the model of nutrition we have adopted – the number of meals during the day, the total protein pool per day, etc., however, the conclusions from the above-described publication enrich us with valuable knowledge and allow for better optimization of the menu to maximize the benefits of training.