Fasting every other day could be the secret to losing weight while staying healthy because it mimics humans’ caveman diet, a new study suggests.

A trial showed that people who ate no food at all for 36 hours then anything they felt like for 12 hours lost more than half a stone within a month.

Crucially, their immune systems remained stable, even after six months, in contrast to many diets which aim to restrict calorie intake consistently each day.

Scientists at the University of Graz in Austria believe the strength of alternate-day fasting (ADF) may lie in its adherence to hunter-gatherers’ patterns of eating thousands of years ago, when food was not available every day.

However, they warn that it may not be suitable for everyone and that further studies need to prove its safety over the long-term.