Michal, this is a bit of a complex one but certainly there’s a bit of evidence that consuming protein immediately after a strength workout is helpful. Part of the issue is that not everyone enters the training in the same state of nutrition. That is to say in an intervention that is done after the training is different for those that might be entering in a fasted state versus those that eat before training. Personally my take on it is to make sure to eat before strength training then whether or not you can eat directly afterwards is not as big of concern. The benefit to taking in protein directly after training is probably small and somewhat debatable but the effort involved is also quite small so I feel like why not maximize the potential results. Here is a very thorough study that discusses basically exactly what we’re trying to figure out here.
Understandable if you don’t want to wade through that here is a short excerpt from the conclusion.
Practical nutrient timing applications for the goal of muscle hypertrophy inevitably must be tempered with field observations and experience in order to bridge gaps in the scientific literature. With that said, high-quality protein dosed at 0.4–0.5 g/kg of LBM at both pre- and post-exercise is a simple, relatively fail-safe general guideline that reflects the current evidence showing a maximal acute anabolic effect of 20–40 g [53, 84, 85]. For example, someone with 70 kg of LBM would consume roughly 28–35 g protein in both the pre- and post exercise meal. Exceeding this would be have minimal detriment if any, whereas significantly under-shooting or neglecting it altogether would not maximize the anabolic response.