Water fasting doesn't make body remove all cancer, Alzheimer's cells

AAP FactCheck - The co-author of a study being cited with claims that fasting can remove all cancer and Alzheimer's cells from the body says that's not true.

The expert says that fasting may enhance other medical treatments, but it cannot cure cancer or Alzheimer's disease on its own.

The claim appears in a Facebook post that includes an image of Nobel Prize-winning cell biologist Yoshinori Ohsumi by the Healthy and Natural World website.

"When the human body is hungry, it eats itself, it does a cleansing process, removing all sick cells, cancer, aging cells, and alzheimer's," the overlay text on the image says.

Healthy and Natural World, which made the Facebook post, is also the source for the linked article. (Facebook/AAP)

The first comment includes a link to a 2019 Healthy and Natural World article examining the benefits of water fasting - consuming only water and abstaining from food for a specified time.

The article states that one of the greatest short-term benefits is a process called autophagy, whereby metabolic processes in the body eliminate dysfunctional cell components, helping to "recycle cells and protect against chronic health conditions and neuro-degenerative diseases."

Yoshinori Ohsumi is an expert on autophagy.

The article contains more nuanced statements, saying autophagy can help prevent cancer.

However, unlike the Facebook post, it does not claim autophagy can completely remove all cancer cells from the body.

The article also states that autophagy protects patients against the side effects of chemotherapy and radiotherapy.

The author cites two journal reviews to support this point: a 2018 review in Brazilian scientific publication Clinics on fasting-mimicking diets and their potential role in cancer therapy and a 2012 Cold Spring Harbour review on the role of autophagy in cancer treatment.

Both reviews said autophagy could suppress tumour development, but it also promotes tumour growth.

Neither review found that autophagy alone could cure cancer.