Can Life Extension from CR be Reconciled with Accepted Evolutionary €eories?

Phelan and Austad [55] responded to Harrison and Archer by noting that the CR adaptation is not restricted to lab animals, and they fell back on McCay’s original reasoning that the response derives from slowing the developmental clock with delayed early growth. In a rejoinder [55], Harrison and Archer correctly point out that mice that begin CR at six weeks and at six months have about the same lifespan and that CR increases lifespan even when begun later in life.