A post resistance training meal is important to provide the amino acids necessary for muscle protein synthesis.
If you don't eat after lifting or don't get enough protein, you won't get the full benefit of the response to the training in terms of protein synthesis.
The only thing that has changed in recent years regarding the advice to eat protein after training is that in the old days people thought it was urgent to eat the protein immediately after training.
There is still reason to eat pretty soon after training, like within an hour or at most, two would be ideal.
Based on research, we know that if you ate protein shortly before training, then the urgency of post-workout protein isn't relatively as high.
That being said, you can also have the post-workout meal like an hour or so after training.
It doesn't have to be immediate.
Still, the best practice, based on science, is to eat a meal with protein both before and after lifting and preferably within a 4 hour window.
The meal does not have to be a supplement or a shake/ drink.
Whole food proteins work fine.
Drinks can be used for convenience if desired.
Carbs are usually eaten as well, but protein is the key nutrient needed for the synthetic protein response.
Strength and physique athletes are not as concerned with glycogen replenishment as endurance athletes.
Research has suggested that protein synthesis can be stimulated with as little as 20 to 25 G protein post-workout, but 40g is more in the ideal ballpark and has been shown to increase protein synthesis even further.
Although eating a meal with protein after training is definitely essential.
It is also important to focus on properly setting the total protein goal for the day and hitting that number every day.
It's ideal for spreading protein throughout the day across multiple meals.
For bodybuilding purposes, a bare minimum of 3 meals is needed, and 4 to 5 is probably superior.
The reason is, there is a limit to how much protein the body can utilize for muscle protein synthesis in one sitting.
So trying to force feed huge amount of protein in one meal including the post workout meal is not going to help increase muscle growth.
It's a misconception that the body can't absorb or digest an extended bolus of protein; it can.
But only so much of that protein can be directed into skeletal muscle tissue for muscle growth.
It seems intuitive to eat a large post-workout meal to replenish energy stores.
But there is no scientific evidence to go out of your way to eat an enormous amount of protein.
Your body simply won't be able to use the excess protein for muscle growth.
Instead, it would get used elsewhere in the body, burned for energy, or if there is a calorie surplus, some could be stored as fat.
So there is no reason to eat that second steak if the first one had 40-50g+ protein.
I've always leaned toward being in favor of the idea of eating closely before and after my workout.
That being said, outside of the essential pre and post-workout nutrition mentioned above, I don't think there is any science showing it makes a massive difference if the calories and macros for the whole day are identical.