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Does Eating Less Extend Life?

Baweg/iStockphoto

Lifespan extension due to dietary restriction has been demonstrated in species ranging from yeast to flies to mice – and even primates too. Credit: Baweg/iStockphoto

By Margo Adler

Dietary restriction extends the lives of species as diverse as yeast, flies and mice, but is this effect simply due to artificial conditions in the laboratory?

The full text of this article can be purchased from Informit.

Scientists have known for decades that one of the most reliable ways to extend lifespan in laboratory animals is to feed them less. Dietary restriction has been studied since the 1930s, and the lifespan extension effect it elicits has been demonstrated in species ranging from yeast to flies to mice. There’s even some evidence it occurs in primates too.

Research into the underlying mechanisms that drive the extended lifespan effect of dietary restriction is progressing rapidly, with great hopes pinned on the potential applications for human health. But an obvious question remains unanswered: why would eating less prolong life? More specifically, what is the evolutionary significance, if any, of this seemingly perplexing response that is shared so broadly among species?

One prominent evolutionary theory to explain the lifespan extension effect has prevailed in the dietary restriction literature for decades. The Adaptive Resource Reallocation Hypothesis takes into account the fact that dietary restriction not only extends lifespan but also reduces reproduction. The hypothesis suggests that in times of famine, animals have evolved to redirect their nutritional resources away from reproduction and into somatic (body) maintenance instead. This resource re-allocation is thought to help animals outlive the famine and hopefully reproduce later.

In a recent...

The full text of this article can be purchased from Informit.