This is an "ask me anything" (AMA) episode, with Prof. Stuart Phillips of McMaster University. Prof. Phillips takes questions on protein intake, sources, muscle function, and healthy ageing. To listen to the full AMA, click here to subscribe to Sigma Nutrition Premium. Questions answered:   [04.28] What is muscle protein balance? [05.32] Why is the focus always on muscle protein synthesis? [07.14] Is MPS a good proxy measure for outcomes we care about (e.g. muscle growth/repair)? [10.37] What's the difference between 'whole body protein synthesis' and 'muscle protein synthesis'? [12.57] We're starting to see commercially available whey that has been produced by bacteria engineered to synthesize whey protein directly from nutritional substrate. It seems like we should expect this to have directly comparable effects given the identical molecular structure. Is there any reason to think this bacterially synthesized whey will have any different effects that whey from dairy? [15.50] Does the literature still show that an additional dose of plant-derived protein is required to equate a similar response from animal protein? [26.39] During post-exercise conditions does protein ingestion stimulate MPS for longer than the usual 2-3 hour period reported in rested conditions? [27.49] Considering the growing interest in fasting protocols (both TRF and longer fasting protocols) - what would you recommend in these circumstances for the preservation / growth of muscle mass. Would it differ between IF/TRF and longer (1-3 day) fasts? [34.58] Is it a waste to take too much protein powder at once because some of it won't get absorbed? [42.50] Does protein powder lose some of its quality if boiling water is added due to protein denaturation? [47.05] Would you please share your opinion about how you evaluate protein status in the body? [50.51] I am now over 60 and lift heavy twice a week. What would be a reasonable body fat % for me to aspire to and how much daily protein should I be targetting in my diet? Subscribe to Premium