New fasting-like diet could reverse your biological age, study claims

New fasting-like diet could reverse your biological age, study claims

A study has shown that cycles of a diet that mimics fasting can reduce signs of immune system ageing.

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Published: February 20, 2024 at 10:00 am

Move over intermittent fasting, the Atkins diet, the Dukan diet, keto, paleo, vegan, Mediterranean and all the rest — there's a new way of eating on the block which can not only make you healthier but also keep you young.

At least all that's according to one new study led by the University of Southern California Leonard Davis School of Gerontology. It suggests that cycles of a fasting-mimicking diet (FMD) can significantly lower risk factors for disease and reduce biological age in humans. 

The FMD, developed by Prof Valter Longo and his team, involves a five-day diet high in unsaturated fats and low in overall calories, protein and carbohydrates. Mimicking the effects of a water-only fast, the FMD provides necessary nutrients while making fasting more manageable for individuals. 

During the five-day fasting period, participants were allowed to consume specified portions of plant-based soups, energy bars, energy drinks, chip snacks and tea. They were also given a supplement so they didn’t miss out on all important vitamins, minerals and essential fatty acids. 

Previous research has demonstrated various health benefits of FMD, including promoting stem cell regeneration, reducing chemotherapy side effects and diminishing signs of dementia in mice. This recent study focused on the effects of FMD on immune system ageing, insulin resistance, liver fat and biological age in humans.



To get the results, the team analysed two groups of men and women aged 18 to 70. Participants underwent 3-4 monthly cycles of the FMD, where they followed the diet for five days and then resumed their normal diet for 25 days.

The results appeared promising. Blood samples from FMD participants showed reduced diabetes risk factors, including lower insulin resistance and decreased average blood sugar levels. 

Magnetic resonance imaging (MRI) revealed a reduction in abdominal and liver fat, indicating a decreased risk of metabolic syndrome – a group of health issues that put you at risk of type 2 diabetes or conditions that affect your heart or blood vessels. Moreover, the FMD cycles appeared to rejuvenate the immune system. 

According to Longo, the results of the studies were particularly convincing owing to the different ways in which biological age was measured. "These studies were not only focused on determining biological age by measuring a set of blood markers demonstrated to predict mortality but also measured insulin resistance, liver fat and the immune system ageing profile by more standard tests," he told BBC Science Focus.

Analysis of the data from both clinical trials demonstrated that FMD participants had reduced their biological age by an average of 2.5 years. This doesn’t mean they look two years younger, but it does reflect how well cells and tissues are functioning.

"This is the first study to show that a food-based intervention that does not require chronic dietary or other lifestyle changes can make people biologically younger," Longo said.

Longo hopes these findings will encourage even more doctors to recommend FMD cycles to patients with elevated disease risk factors and the general population interested in enhancing their health and vitality.

“Although many doctors are already recommending the FMD in the United States and Europe, these findings should encourage many more healthcare professionals to recommend FMD cycles to patients with higher than desired levels of disease risk factors as well as to the general population that may be interested in increased function and younger age,” he added.

Longo suggested that healthy people between the ages of 20 and 70 should consider trying FMD two to three times a year. However, he also cautioned that "there are some concerns when taken with certain diabetes medications so anyone with a disease should first talk to their doctor".

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About our expert:

Valter Longo is the Edna M. Jones professor of gerontology and biological sciences and director of the Longevity Institute at the University of Southern California–Leonard Davis School of Gerontology, Los Angeles, one of the leading centres for research on ageing and age-related disease. He is also the director of the Longevity and Cancer Program at the IFOM Institute of Molecular Oncology in Milan, Italy and has authored several books on the topic of diet and nutrition.