Low protein intake is associated with poor bone strength. Break a hip in the golden years and the chance of death over the next 12 months is 1 in 3. It took me 2 years to reverse osteoporosis and protein intake was one factor.
Body builders eat 6 small meals per day with protein at each meal. The morning meal should always be protein focused.
I wonder what the relationship is to loss of oxygen utilization loss (VO2 max, FTP, etc) and muscle loss as we age. Which muscle fibres do we lose? Fast twitch? If so, the lactate that FT provides as fuel for slowtwitch fibres is lowered. What is clear is a gradual loss in both muscle mass and VO2 max from approx. age 35 until 60 or 65 and then both take a sharper decline. Coincidence?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6610901/