Protein, how much to eat per meal? A systematic review in maximizing the muscle protein synthetic response in resistance-trained athletes

Abstract

It is common practice in strength sports to spread out nutrient intake, and more specifically protein, into small amounts during the day with the belief that this is not only optimal but absolutely necessary in order to render in optimal response in terms of protein utilization and growth. Moreover this notion mainly stems from the believe that only a limited amount of protein (20 – 30 g-1) can be utilized per meal. OBJECTIVE: To evaluate existing evidence into the amount of protein that might optimize the muscle protein synthetic response (MPS) in the post prandial period. DESIGN: Systematic review of randomized controlled trials (RTCs). SUBJECTS: ‘Healthy’ adult subjects (18 – 64 years of age) either after an acute bout of resistance training and/or systematic involvement in resistance training (minimum of 3 days/week). RESULTS: 56 studies were identified as primary research, of which 12 were assessed for eligibility. Of these 12 studies, 3 met the predetermined inclusion criteria. Synthesis of the evidence showed included studies varied considerably in terms of study design, quality and outcomes, yet showed no evidence that only a limited amount of protein can be utilized per meal. CONCLUSION: At this point there is no evidence that only 20 – 30 g-1 of protein per meal can be utilized per meal by resistance trained athletes while on the other hand there is, at best, very minor evidence that more than these amounts ( ~ 40 g-1) might stimulate MPS to a greater degree. Further studies should focus on comparing various amounts of protein using ‘realistic’ administration of nutrients as well as with the usage of ‘realistic’ training protocols.