There has been an interesting series of mice-experiments published. As a key result it emerged, that CR in mice without extended fasting is not life-extending. Fasting alone without CR does extend mice lifespan.
All previous experiments in the past decades with CR in mice also implemented fasting - so there is the real possibility, that it's indeed mostly fasting leading to the lifespan effects observed, not CR.
A discussion of that is currently ongoing in the forum of the Caloric Restriction Society:
https://www.crsociet...or-cr-benefits/
I recommend that everyone interested in CR is following that discussion.