Protein timing is the question of how long after you workout should you eat protein. Until fairly recently, conventional wisdom was that there was a 30-60 minute window to eat protein after a workout to maximize protein muscle synthesis.
Here’s a good article on Protein timing (The New Rules of Protein Timing) which states that there’s newer science which indicates that the window is wider and also affected by what you ate earlier.
Here’s one of the studies (Human Kinetics Journals, Volume 19 Issue 2, April 2009. Effect of Protein-Supplement Timing on Strength, Power, and Body-Composition Changes in Resistance-Trained Men . Jay R. Hoffman, Nicholas A. Ratamess, Christopher P. Tranchina, Stefanie L. Rashti, Jie Kang, Avery D. Faigenbaum).
Results indicate that the time of protein-supplement ingestion in resistance-trained athletes during a 10-wk training program does not provide any added benefit to strength, power, or body-composition changes.
Here is another similar result from analysis of many studies (Journal of the International Society of Sports Nutrition 2013 10:53, The effect of protein timing on muscle strength and hypertrophy: a meta-analysis. Brad Jon Schoenfeld, Alan Albert Aragon and James W Krieger.):
These results refute the commonly held belief that the timing of protein intake in and around a training session is critical to muscular adaptations and indicate that consuming adequate protein in combination with resistance exercise is the key factor for maximizing muscle protein accretion.