As you may know, researchers Michael Rose and John Phelan have joined the ranks of those marshalling scientific arguments against calorie restriction (CR) as a means of significantly extending healthy life span in humans - "significantly" in this case meaning by a few decades. Regardless of the merits of their paper and models - from the discussions on the GRG mailing list, they form a good stab at the topic, but are far from watertight - I think that we should remember that we're talking about something that can, at best, assuming folk like Michael Rose are wrong, slow aging by a handful of years. This is far, far better than nothing - and indeed, I'm very much the calorie restriction advocate - but it pales before what would be possible in the years ahead if sufficient funding were devoted to developing real anti-aging medicine.
We need rejuvenation therapies. The idea of finding a way to slow aging with CR or sirt1 or the latest hope Klotho all seem like misplaced hopes to me. Klotho may eventually deliver the same (limited) benefit as CR but without the perpetual hunger and might be worth taking some day. But we really need gene therapies, cell therapies, immunotherapies that can remove extracellular junk, and other therapies that can do repair.
Calorie restriction is good for you, and is currently the best, most backed method for extending your healthy life span. Yet this is only true because there are no other available methods ... and calorie restriction isn't the starting place for the healthy life extension medicine of the future. That starting place is funding for medical research programs like Aubrey de Grey's SENS - and lots of it.