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Following a fasting-mimicking diet could help lower the risk for multiple diseases. Alina Hvostikova/Stocksy
  • A study showed a fasting-mimicking diet (FMD) lowered insulin resistance, liver fat, inflammation, and other markers associated with aging.
  • The diet is based on the consumption of formulated food with controlled levels of dietary macros on days 1–5 and then eating normally for 25 days out of a month.
  • This fasting-like diet style is not suitable for everyone, including pregnant people and older adults.

Three cycles of a so-called fasting-mimicking diet (FMD) was shown to reduce biomarkers associated with insulin resistance, liver fat in humans, and other markers associated with aging.

USC Leonard Davis School Professor Valter Longo, the senior author of the new study, designed the FMD. This five-day diet is high in unsaturated fats and low in protein, carbohydrates, and calories.

The study examined the diet’s impact in two clinical studies, which included men and women between the ages of 18 and 70. Participants who followed the fasting-mimicking diet went through 3-4 monthly cycles, following the FMD for 5 days and adhering to a normal diet for the other 25 days.

Results showed that patients in the FMD group had less insulin resistance, lower HbA1c results, and better fasting glucose results. They also had less abdominal fat and liver fat, along with improved immune system markers suggesting lower inflammation.

In addition, both clinical studies showed that those who followed the FMD had lowered markers associated with biological aging by 2.5 years on average.

The study was published in Nature.

This clinical study, involving 100 participants, indicated that a plant-based fasting-mimicking diet done for 5 days a month could reduce the biological age of people after only three monthly cycles and without changing their lifestyle.

The researchers provided participants with food that had been formulated to contain certain proportions of macro- and micro-nutrients, such as soups, energy bars, snacks, and teas, for days 1-5. These were provided by the company L-Nutra Inc., a company that sells ready-packaged meals for people who are fasting. Two of the authors ‘have equity interest in L-Nutra’, the study read.

The first study carried out by these researchers was published in Metabolic Health and Disease in 2023, and showed similar results.

“The results are particularly convincing because both studies, one done in Los Angeles and one in Tennessee, showed similar effects on the reduction of biological age by 2.5 years as measured by the biome method developed by Morgan Levine at Yale but also showed parallel evidence of rejuvenation or improved function/health of multiple system including the immune system, the liver and the endocrine system as measured by standard methods,” Prof. Longo told Medical News Today.

“The next step is to continue to allow many universities to perform clinical trials to test how cycles of this standardized plant-based FMD, which comes in a box like medicine, can help people stay younger but also prevent or treat diseases like diabetes, CVD, cancer, and Alzheimer’s considering that biological age and multi-system dysfunction are the major risk factors for these diseases.”
— Professor Valter Longo

“We also hope that these studies will convince doctors to add the FMD to their toolkit for disease prevention and possibly treatment,” he added.

There are numerous ways this diet can improve overall health.

Reducing inflammation

“The FMD does exactly what it is named after- mimics fasting,” said Dr. Nicole Avena, nutrition consultant, assistant professor of neuroscience at Mount Sinai School of Medicine, visiting professor of health psychology at Princeton University, and author of Sugarless.

“This diet is beneficial to balancing blood sugar, improving insulin resistance, and reducing overall inflammation throughout the body. By giving your body time to rest, rather than digest, it allows us to heal inflammation and put energy towards more pressing internal ‘issues,’” she explained.

Lowering biological age and risk factors for disease

Many lifestyle diseases, such as diabetes or cardiovascular disease are associated with shortened lifespan.

“These diseases raise inflammation within the body and allow for reactive oxygen species (ROS) to multiply,” Avena explained. “ROS in excess cause disease, therefore aiming for a low-inflammatory lifestyle like FMD is beneficial for aging.”

“Biological age, in particular, is interesting because it is genuinely what age we feel versus what age we really are. The more inflammation and disease we have determines our abilities to perform acts of daily living,” she added.

While the clinical consensus is that the FMD is generally safe, there are some people who should not follow this diet.

“If you are pregnant or trying to conceive, and if you are considered an older adult, the FMD is not for you,” Avena said.

“During pregnancy, we have higher metabolic demand, and in old age, we do not have as fast of a metabolism as we do when we are younger,” she added.

During pregnancy, getting enough nutrients is essential for the health of the baby and parent.

For seniors, fasting is usually not recommended, especially if they already have chronic health issues.

Usually, the FMD consists of higher-fat foods while staying relatively lower in protein.

“This is a great time to try a Mediterranean-style diet, which includes beans, olive oils, fatty fish, and whole grains,” said Avena.

“Remember, you are trying to eat under your estimated calorie needs for 5 days while drinking plenty of water. Doing this once a month is the way it is planned, but you should continue to incorporate healthy foods like those included [in] a Mediterranean diet throughout the month,” she explained.