Hunger can be healthy - within reason, obviously. Australian scientists have come up with a new theory about why eating sporadically, like animals in the wild, is likely to make people age better and live longer.
They believe hungry animals recycle nutrients stored in their cells. This means they need less food to survive and it also promotes cell repair.
In the wild, this recycling of nutrients allows animals to breed during hard times, promoting survival of the herd.
In laboratory animals, it reduces cell deterioration and the risk of cancer in individuals, and is likely to have similar benefits for people.
''Wild animals don't often die of cancer and diseases of old age. They tend to die young as a result of environmental hazards and exposure to parasites,'' said Dr Margo Adler, lead author of a study published in the journal BioEssays.
Lab animals and many modern humans don't have these issues.
''People might be able to reap some of the lifespan and anti-cancer benefits from dietary restriction or interventions that mimic its effects,'' said Dr Adler, a University of New South Wales evolutionary biologist.
She praised the intermittent fasting concept made popular by the BBC doctor Michael Mosley's 5:2 diet, which could mimic the laboratory benefits of diet restriction.
''The 5:2 diet is the most promising popular diet around,'' she told AAP.
''Many of the popular diets are not based in science. But researchers have found that fasting can have long-term benefits similar to dietary restriction.''
However, people on the 5:2 diet might benefit from reducing their protein intake as well as calories on fasting days.
''A diet with more carbs than protein is thought to have beneficial long-term effects.''
However, this was not the best diet for weight loss, she said.
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