I think CR is somewhat most consistent thing found to work in many animal models. Maybe in future, we will also figure out that more than calories it has been the synergistic effect of reducing certain molecules in the diet. It's interesting to use CR as a proxy, for now, to figure out the molecular pathways. If we know the pathways we can have some guess on what genes might be involved, what are the gene-environmental interactions apart from a diet that slows or accelerates ageing. If I compare the field of ageing with particle physics we have just shot electrons on a gold foil to guess the structure of atoms. It's a long way until we get to the standard model.