Clinical trial shows bouts of fasting lowers risk of age-related disease


A drastic diet for five days a month produces equally drastic results. Amy Middleton reports.


Fasting just five days every month brings big health benefits.
Michaela Begsteiger / Getty Images

Fasting can bring significant health benefits, but it’s difficult to implement: there can be adverse effects, and, on the whole, it isn’t much fun.

In light of this, experts are now testing the effects of fasting-mimicking diets, or FMDs, on human health. A new study in Science Translational Medicine suggests an FMD could have significant benefits for ageing-related diseases, reducing the risk of diabetes, cancer and heart disease.

Led by Min Wei and Sebastian Brandhorst from the University of Southern California, Los Angeles in the US, the research incorporates an experimental FMD that eases participants into consuming 3,000 kilojoules a day – down from an average of 8,700 kilojoules – for five days a month.

“Prolonged fasting, in which only water is consumed for two or more days, reduces pro-growth signalling and activates cellular protection mechanisms in organisms ranging from single-cell yeast to mammals,” the researchers explain.

But going without food is difficult, and can be hazardous: “Calorie restriction or changes in dietary composition can enhance healthy ageing, but the inability of most subjects to adhere to chronic and extreme diets, as well as potentially adverse effects, limits their application.”

FMDs are plant-based regimens that emulate the effects of fasting on levels of glucose, ketone bodies and growth hormones. Both fasting and FMDs have been shown to reduce the rates of cancer and multiple sclerosis in mice.

Wei, Brandhorst and colleagues wanted to test the potential of the diet to affect factors associated with metabolic syndrome, a condition that often leads to heart disease and shortened life span.

Over a five-day diet period each month, participants ate from a low-protein, low-sugar menu with a high concentration of unsaturated fats, as well as taking supplements rich in minerals, vitamins and essential fatty acids.

They stuck to the diet for three months while the scientists recorded effects on risk factors for ageing-related diseases.

Over the period, participants lost weight and body fat, and their blood pressure and cholesterol levels dropped. Positive effects were more pronounced among those with a high risk of age-related disease.

Crucially, no adverse side effects were observed. “Cycles of a five-day FMD are safe, feasible, and effective in reducing risk factors for ageing and age-related diseases,” the researchers write.

The team says larger studies among patients with diagnosed diseases, or at particularly high-risk, will help confirm the benefits of FMDs on disease prevention and treatment.

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Amy Middleton is a Melbourne-based journalist.