'Caveman diet' of fasting followed by feasting is the secret to losing weight
Fasting every other day could be the secret to losing weight while staying healthy because it mimics humans' caveman diet, a 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 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 are needed.
Published in the journal Cell Metabolism, the study recruited 60 participants who were enrolled either into an ADF group, or into a control group allowed to eat whatever they wanted.
The scientists found that, on average, the dieters ate normally during the 12 hours they were at liberty to eat an unlimited amount.
Overall, they reached an average calorie restriction of around 35pc and lost an average of 3.5kg after four weeks.
"Why exactly calorie restriction and fasting induce so many beneficial effects is not fully clear yet," said Prof Thomas Pieber, head of endocrinology at the Medical University of Graz.
Prof Frank Madeo, his colleague, added: "Our physiology is familiar with periods of starvation followed by food excesses."
Previous studies had suggested that calorie-restrictive diets can result in malnutrition and a decrease in immune function. In contrast, even after six months of ADF, the participants' immune function appeared to be stable.