Protein Intake Timing

Esmark et al. (2001) -- Post-workout Protein Intake Might Stimulate MPS 

Esmarck et al. (2001) conducted a study examining the effects of postexercise protein intake on muscle hypertrophy in elderly individuals. The study involved 13 elderly men who completed a 12-week resistance training program, consisting of sessions held three times per week. Throughout the program, participants were administered an oral carbohydrate-protein supplement either immediately following exercise or two hours post-exercise.

Upon completion of the 12-week program, various measurements including strength levels and body composition indicators such as lean body mass percentage and cross-sectional area of the quadriceps were recorded. The researchers observed a significant increase in both strength and lean muscle mass among the group that received protein supplementation immediately after exercise.

Candow et al. (2006)-- Protein Intake Timing Has No Effect On MPS

In a parallel study, Candow et al. (2006) employed a similar research design but yielded contrasting outcomes. The investigation enlisted 19 older men who were divided into two groups, with one group receiving a protein supplement before workouts and the other group receiving it after workouts. Following 12 weeks of resistance training, assessments were conducted on lean tissue mass and strength.

The results indicated an increase in lean tissue mass within both groups; however, no significant differences were observed between the pre and post workout supplement trials.

Wirth et al. (2020)-- The Consensus

In light of the conflicting findings regarding the impact of protein intake timing on muscle protein synthesis (MPS), Wirth et al. (2020) undertook a comprehensive meta-analysis to elucidate the influence of protein supplementation timing on body composition, muscle strength, and synthesis. Drawing from data collected from 65 studies involving 2900 participants, the meta-analysis aimed to provide a clearer understanding of the relationship between protein intake timing and its effects on these parameters.

The meta-analysis findings revealed that protein supplementation following resistance training positively influenced lean body mass irrespective of the timing of protein intake. Interestingly, the majority of studies suggested that improvements in lean body mass were not significantly influenced by the timing of protein intake—there was no statistical difference in MPS observed between pre- and post-workout protein supplementation. The meta-analysis concluded that protein intake stimulated MPS independent of its timing.