The Idea of an anabolic window, or the thought in which you must consume protein within one hour of finishing a workout; stems from the idea that a workout breaks down muscle, and that the nutrients must be immediately replenished.
It is believed in some extreme realms that if you miss this window then you have wasted your workout entirely. Timing of meals or more specifically post workout windows have a small effect on lean muscle gains; in fact, total daily protein intake has a bigger impact on muscle growth and repair then the timing in which it is consumed. This is because weight training alone elevates muscle protein synthesis (muscle building). Instead, this “window” for protein synthesis from food is closer to 5 hours before or after your workout. For example, if you consume a meal or protein 1-2 hours before your workout and then workout for an hour, you have around 2-3 hours to get your next meal as opposed to the prior 30-60-minute window. With this in mind, be sure to get a meal in your body as soon as possible post training, but one does not have to worry if it does not happen until a few hours later. Lastly, be sure to keep in mind that total daily protein intake has a higher effect than that of a singular post workout meal.