For centuries many cultures have used fasting as a natural remedy to fight sickness and ageing, and scientists at the University of California have now proven that these age-old techniques replenish white blood cells and restore functional wellbeing to our immune systems.

The scientists behind the 2014 study say the results show how important fasting is to fight off infection and disease, particularly for those of us with damaged immune systems, such as cancer patients on chemotherapy.

We now know that in just three days of fasting, new white blood cells are created – and our entire immune systems regenerated.

How does this work? During a fast, our bodies not only use glucose and fat stores to expel toxins, but also break down white blood cells damaged (that are our friends in fighting disease) by unloading useless, tired, old and ones to save energy.

Professor Volter Longo, of the University of California, told London’s Telegraph that this process “gives the ‘OK’” for our stem cells to “rebuild the entire system”.

“Now, if you start with a system heavily damaged by chemotherapy or ageing, fasting cycles can generate, literally, a new immune system.”

“There is no evidence at all that fasting would be dangerous while there is strong evidence that it is beneficial,” Professor Longo said.

Fasting also unloaded a nasty hormone known as the PKA enzyme, which is linked to ageing and also increases our risk of cancer and tumour growth.

In the ground-breaking study that dispelled criticisms of using fasting to increase immunity, fight off disease and restore wellbeing to our lives, human subjects fasted for between two and four days over a six-month period.

Tanya Dorff, assistant professor of clinical medicine at the USC Norris Comprehensive Cancer Center and Hospital, agreed that fasting repairs the “significant collateral damage to the immune system” caused by chemotherapy, but advised we only fast under the guidance of a health professional.

To read more about the study’s findings on how fasting for three days can regenerate entire immune system, click here.