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Does protein supplementation augment adaptations to endurance exercise training? 
Great to see a meta-analysis on this topic by Lin, @adaptation_84, and coworkers.
A thread with potential implications for endurance athletes
1/10 https://www.clinicalnutritionjournal.com/article/S0261-5614(20)30687-7/fulltext#.X-HlRkkuvqs.twitter
Great to see a meta-analysis on this topic by Lin, @adaptation_84, and coworkers.
A thread with potential implications for endurance athletes
1/10 https://www.clinicalnutritionjournal.com/article/S0261-5614(20)30687-7/fulltext#.X-HlRkkuvqs.twitter
When all studies with VO2max/peak as outcome variable (n = 9) are taken together, protein supplementation is associated with a greater increase in VO2peak (0.89 mL / kg / min) during a training program of at least 4 weeks. 2/10
The meta-analysis included a wide variety of populations, supplementation regimens, and training programs. Sub-analyses show that the added value of protein can be attributed to studies with clinical populations or untrained individuals (baseline VO2peak <40 mL/kg/min). 3/10
It is plausible that these untrained subjects in particular had a low protein intake at the start of the study. However, this factor was not included in the meta-analysis, probably because many studies do not report baseline nutritional intake. 4/10
When participants' baseline VO2max was> 40 mL/kg/min, exercise duration was> 3.5 hours per week, or 'HIIT' was included in exercise regimen, there seemed little benefit from protein supplementation. This is in line with our recent RCT on this topic. 5/10 https://journals.lww.com/acsm-msse/Fulltext/2019/10000/Protein_Supplementation_Does_Not_Augment.8.aspx
Also very recent studies on this subject, which have not yet been included in the meta-analysis, show no added value of protein supplementation in moderately to well-trained individuals. 6/10
https://jissn.biomedcentral.com/articles/10.1186/s12970-020-00376-3 https://link.springer.com/article/10.1007/s00421-020-04450-1
https://jissn.biomedcentral.com/articles/10.1186/s12970-020-00376-3 https://link.springer.com/article/10.1007/s00421-020-04450-1
So, is there no benefit at all from protein supplementation to be expected in moderately to well-trained individuals? This is still difficult to say, because the number of well-conducted studies in moderately to well-trained individuals is still small. 7/10
My expectations based on this meta-analysis and recent studies, is that the effect of protein supplementation is likely to be small or absent, at least in terms of VO2max/peak. 8/10
Still, protein supplementation was found to be superior in increasing lean body mass during endurance training. While this is not usually the intended purpose of endurance training, it may be beneficial for some, but not necessarily for all endurance athletes. 9/10
When aiming for endurance specific adaptions there appears to be little reason to exceed the current recommendations for protein intake for endurance training (1.2 to 1.7 g/kg/BM). Some athletes may find it convenient to achieve these numbers through protein supplements. 10/10
