No, it isnt. I generally call things bro science but this one isnt. Here is one study that shows this:
http://ajpendo.physiology.org/content/292/1/E71.short There are multiple others. However, the requirement to eat after working out is overstated. It is necessary if you exercise while fasted but not if you do not exercise for more than an hour or so and you ate something beforehand. In general, you should have some protein and carbs around when you workout. It doesnt have to be after and it doesnt have to be before but it has to be one or the other.