If protein restriction causes activation of autophagy at the end of periods between meals (for example before breakfast), then it works to clear out damaged cell components and damaged cells.
That could be part of the effect. Autophagy releases protein, which gets turned back into amino acids.
That is an interesting sentence...but then you have people that deal with things like this:
“
In both in vivo and in vitro systems, inhibition of autophagy ameliorates diseases including SLE, MS, and RA. However, in other cases, it seems to exacerbate diseases such as psoriasis, psoriatic arthritis, and IBD”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6080611/
which is why there is a warning on Chloroquine that it can exacerbate psoriasis.
It seems like for many people striking a balance is difficult