Scientists have known for decades that severely restricted food intake reduces the incidence of diseases of old age, such as cancer, and increases lifespan.
'This effect has been demonstrated in laboratories around the world, in species ranging from yeast to flies to mice. There is also some evidence that it occurs in primates,' says lead author, Dr Margo Adler, an evolutionary biologist at UNSW Australia.
The most widely accepted theory is that this effect evolved to improve survival during times of famine. 'But we think that lifespan extension from dietary restriction is more likely to be a laboratory artefact,' says Dr Adler. Lifespan extension is unlikely to occur in the wild, because dietary restriction compromises the immune system's ability to fight off disease and reduces the muscle strength necessary to flee a predator.