Diets that mimic fasting could ‘reverse aging process’, study finds

Image of an empty plate to illustrate fast-mimicking diets. (Getty Images)
New research has found fast-mimicking diets could slow down ageing. (Getty Images)

Diets that mimic fasting may be able to make a person "two-and-a-half years younger" by reducing their biological age, a new study has suggested.

Researchers found that a fasting-mimicking diet (FMD) can lower insulin resistance, reduce liver fat, and slow immune system ageing.

It can also decrease the risks of age-related illnesses, such as cancer, diabetes, and heart disease.

When these benefits are combined, researchers found this fasting-like diet can result in a lower biological age for humans.

Created by a laboratory at the USC Leonard Davis School of Gerontology in California, a fasting-mimicking diet is a five-day diet which is high in unsaturated fats and low in overall calories, protein, and carbohydrates.

It is designed to mimic the effects of a water-only fast while still providing the necessary nutrients.

The style of fasting is also supposed to make it easier for people to follow and stick to this kind of diet in practice.

"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," senior author Professor Valter Longo explains.

"This is based on both changes in risk factors for ageing and disease, and on a validated method developed to assess biological age."

Woman drinking water. (Getty Images)
What are fast-mimicking diets? (Getty Images)

For the research Professor Longo and his team analysed the effects of the FMD in two clinical trial populations – each with men and women between the ages of 18 and 70.

Participants underwent three to four monthly cycles of the FMD, during which they adhered to the diet for five days and then ate a ‘normal’ diet for 25 days.

While sticking to the FMD, they ate things like plant-based soups, energy bars, energy drinks, crisps, and tea – all of which were portioned out over the five days.

They were also given a supplement which provided high levels of minerals, vitamins, and essential fatty acids.

Meanwhile, a control group was instructed to eat either a ‘normal’ or Mediterranean-style diet – which is what the FMD participants ate in their ‘time-off’.

Results, published in the journal Nature Communications, revealed that those in the FMD group had lower risk factors for diabetes, including less insulin resistance and lower HbA1c levels.

They also had decreased abdominal and liver fat, which is associated with a reduced risk of metabolic syndrome, and an increased lymphoid-to-myeloid ratio, which is an indicator of a more youthful immune system.

Further statistical analysis of both clinical studies also showed that the FMD participants had reduced their 'biological age' by two and a half years on average.

‘Biological age’ is a measure of how well a person’s cells and tissues are functioning, as opposed to chronological age.

"This study has shown for the first time evidence of biological age reduction from two different clinical trials, accompanied by evidence of rejuvenation of metabolic and immune function," Professor Longo explains.

Woman eating. (Getty Images)
Research has suggested there could be some health benefits to FMDs. (Getty Images)

First author Professor Sebastian Brandhorst adds: "Our study also lends more support to the FMD’s potential as a short-term, periodic, achievable dietary intervention that can help people lessen their disease risk and improve their health without extensive lifestyle changes."

The research team from USC Leonard Davis hopes that their findings will encourage more doctors across Europe and the US to recommend the FMD to patients with higher disease risk factors, as well as to typically 'healthy' people who may be interested in the other benefits – including slowing the ageing process.

Previous research by Prof Longo has indicated that brief, periodic FMD cycles can promote stem cell regeneration and lessen chemotherapy side effects.

Meanwhile, trials on mice have found that the FMD can reduce the signs of dementia.

However, the new study was the first to demonstrate the effects of the FMD on insulin resistance, liver fat, immune system ageing, and biological age.

What is a fasting-mimicking diet?

FMDs, or Fasting Mimicking Diets, are diets designed to mimic the effects of fasting on the body without requiring complete abstinence from food.

"Typically, these diets involve significantly reducing calorie intake for a set period, usually ranging from three to five days, while still providing essential nutrients," explains gut health expert and owner of supplements brand Miracle Leaf, Agnieszka Kozlowska.

"The idea is to trick the body into a fasting state, prompting a range of physiological responses similar to those seen during prolonged fasting."

Kozlowska says one of the key benefits of FMDs is their potential to promote cellular rejuvenation and repair.

"When the body enters a fasting state, it initiates processes such as autophagy, where cells break down and remove damaged components," she explains. "This can help clear out old and dysfunctional cells, making way for new, healthier ones.

"By mimicking fasting, FMDs can stimulate these repair mechanisms, potentially slowing down the ageing process and promoting overall cellular health."

Another area where FMDs show promise is in supporting gut health.

"The gut microbiota, comprised of trillions of microorganisms, plays an essential role in digestion, immune function, and overall health," Kozlowska explains.

"Research suggests that FMDs can help promote a healthy balance of gut bacteria by creating an environment that prevents harmful microbes, promoting the growth of beneficial ones," she continues.

"While more research is needed to fully understand the effects of FMDs, the preliminary evidence is promising."

Additional reporting SWNS.

Gut health: Read more

Watch: Experts predict 2024 TikTok health and fitness trends