from https://www.outsideonline.com/health/training-performance/fo... ... After a heroic research effort that took 2.5 years and 500,000 euros, he and his colleagues had managed to shepherd a large group of frail, elderly subjects through a six-month strength-training program. Those who had taken a daily protein supplement managed to pack on an impressive 2.9 pounds of new muscle. Success! Old people could be strong!…
This is significantly out of line with other research I've seen. Marusic et al. (2021) meta-analysis[1] found an average muscle loss of ~2% after 5 days. It did not report average absolute muscle loss, but the average person has about 1/3 of bodyweight as muscle, so at an average weight of ~180 pounds, that would represent 1.2 pounds of muscle loss in a ~week, not 3.1 pounds.