SENS and Caloric Restriction

Caloric restriction (CR), reducing caloric intake by 25+% without reducing nutrients by other measures, is the only method proven to extend maximum lifespan. Such proof has been found in species ranging from fruit flies to dogs.

CR has been found not only to extend maximal lifespan but also to dramatically extend healthy years.

A study on rhesus monkeys has demonstrated an extension in healthy years, a.k.a. healthspan, but hasn't been run long enough to demonstrate that CR extends maximal lifespan in primates. One caveat of such a study in terms of what it says about humans is that larger primates may avoid predation enough for more pro-longevity genes to be selected on. Evolutionary benefits of being bigger may dwarf the benefits of CR. What works well for smaller primates may therefore not be a good test of benefits in larger primates such as ourselves.

This caveat is one reason a significant body of biogerontologists don't expect the increase in human lifespan from CR to be much more than 5-10 years. See here for further argumentation. The matter is open to much debate.

This is not to say that practicing CR is a bad idea. On an individual basis, it could have a profound effect for the following reason. 5-10 extra years may be enough to fully benefit from first-generation medical therapy derived from SENS research (and other future technologies). The extra years gained from the first-generation of therapies could allow one to bootstrap to the second generation, and so on. Adding 5-10 years could then be worth more than just 5-10 years.

As a permanent strategy for extending healthy life, however, CR is not entirely consistent with LMRF’s motto and aim of both more life and more life worth living. CR has been described as an unpleasant experience. Also, though it could improve the relative ability to exercise in later years by slowing degradation, it impairs the ability to exercise earlier in life. This may not appeal to those who came to this page via TourdeSussex.org, the site of LMRF's charity bike ride fundraiser. Meanwhile, there is ongoing research to figure out how to emulate CR without having to go through a near-starvation diet. (CR seems to switch on an anti-aging mechanism connected with a gene called SIR2.)

In comparison to SENS, CR at best slows age-related degradation. This is the nature of targeting metabolic processes and intervening in the aging process itself. (Resveretrol would be another recent example from the popular press.) SENS on the other hand would not meddle in aging but would just let it happen -- then repair selectively which damages are early precursors of age-related degredation and disease. The effect would be the same as "reversing aging", but sidestepping the complexity of metabolic processes of which biogerontologists have very limited knowledge with which to avoid side effects from which natural selection has been careful to steer us.

If you are interested in trying CR, the Calorie Restriction Society and April Smith's CR Diary may be of interest or help to you.