Perhaps this is another pathway that calorie restriction improves health as I would think that ghrelin is likely upregulated in those practicing CR.
Good call IMO and more support to the evolutionary biology theory of CR working as systemic response that helps ensure survival through famine cycles. Remember we evolved through millions of years of feast-famine cycling.
I have long suspected that we are not going to find one mechanism but instead a complex relationship of multiple mechanisms that make up a tiered systemic response to starvation. However there are biological costs and too much of a good thing is still too little in this respect.
There are trade offs that should not be forgotten. Nutritional uptake in relation to physical expenditure balance for a healthy CR regimen becomes very critical because reserves in a sustained CR regimen are generally reduced to absolute biological minimums.
This also lends support to my assertion that dietary needs
change during various phases of life and there is not a one size fits all solution. We must adapt and then keep adapting.