A diet that mimics fasting has rejuvenating effects

How can we halt or stop the metabolic changes that accompany aging, in order to improve or prevent many human diseases? This is the challenge taken up by researchers around the world.

Natural aging, says Professor Valter Longo (Institute of Molecular Oncology, Milan), is in fact accompanied by a deregulation of the immune system, with less resistance to infections, more frequent complications in the event of infection, and greater susceptibility to inflammatory diseases, particularly those of autoimmune.

It also increases the risk of developing metabolic syndrome, with overweight or obesity, insulin resistance, dyslipidemia and abdominal obesity, but also accumulation of fat in the liver (non-alcoholic fatty liver disease or NAFLD).

“ Diet is one of the main levers of intervention on aging “, says Valter Longo. For example, it can modify the microbiota. Likewise, by modifying the quality of carbohydrates, the effects can be major: we know that processed carbohydrates, which are easily digestible and have a high glycemic index, play a central role in accelerating the aging process and mortality.

We could also limit daily calories. Studies in humans indicate that chronically reducing calories by 15 to 20 percent from normal intake levels has powerful effects on risk factors for diabetes, cancer, and cardiovascular disease. Studies in monkeys indicate that calorie restriction (CR) can prevent diabetes or insulin resistance in the vast majority of animals and lead to significant reductions in the incidence of cancer and cardiovascular disease. However, chronic calorie restriction is a harsh intervention that is impractical for the majority of the population and also causes adverse changes that could negate its beneficial effects, including reduced weight and lean mass.

In animals, and perhaps also in humans, lifespan is influenced by the number of hours during which meals are consumed. Rodents that eat within a limited time window (TRF or time restricted feeding) have better health and longevity. Likewise, intermittent fasting promotes protection against multiple diseases in animals and induces lifespan extension, and in humans, reduces insulin resistance and other risk factors for metabolic diseases.

Read: The best forms of intermittent fasting (subscribers)

Fasting is therefore a particularly promising avenue for intervening on aging and its consequences. However, it is not always easy to fast, particularly over long periods, and fasting may be contraindicated in certain situations, certain illnesses, and for elderly populations. Professor Valter Longo and his colleagues at the University of California at Los Angeles therefore developed a diet imitating fasting.

The Fasting Mimicking Diet, or FMD

The fasting mimicking diet (FMD for food-mimicking diet) is a 5-day, low-calorie, low-protein plant-based dietary intervention that can be followed monthly to replicate the effects of fasting. Rather than abstaining from food entirely, as one would during a traditional fast, one consumes small amounts of nutrient-dense foods.

The FMD provides approximately 1100 calories (kcal) on the first day, and 800 on the following days until the fifth day. On the sixth day a transition is made to the normal diet, which is resumed on the seventh for 24 to 25 days before starting a new cycle.

Specific amounts of macro and micronutrients are as follows:

• 43 to 47% of calories in the form of carbohydrates;
• 44 to 46% fat;
• 9 to 11% protein.

There is currently a pre-packaged, ready-to-eat FMD diet created by Dr. Longo. It does not contain gluten or animal products, so it is a type diet vegetarian or vegan. Each delivery contains five days of soups, nut bars, snacks, herbal teas, and vitamin and mineral supplements to prevent deficits linked to low-calorie diets. There is also an omega-3 fatty acid supplement to preserve muscle mass. However, it is possible to design your own low-calorie FMD diet with simple plant-based recipes.

In mice, FMD cycles allow cells and organs to activate degradative processes called autophagy, which target dysfunctional cells. They are followed by regeneration or reprogramming phases during the refeeding period during which new cells or functional cells in greater numbers are generated.

Still in mice, when started at middle age, says Professor Longo, FMD cycles increase lifespan; they reduce the incidence of tumors by 45% and significantly reduce inflammatory diseases.

“ In a previously published human clinical trialhe adds, we compared people who followed 3 months of a standard diet to people who consumed the FMD for 5 consecutive days per month for 3 months. Three cycles of FMD reduced body weight, total body and trunk fat, blood pressure, and insulin-like growth factor 1 (IGF-1) without causing serious adverse effects “.

Three cycles of FMD reduced body weight and insulin-like growth factor 1 (IGF-1) without causing serious adverse effects

In this new study, body mass index, blood pressure, fasting blood sugar, IGF-1, triglycerides, total cholesterol, low-density lipoprotein, and C-reactive protein were more significantly reduced in participants with originally high levels of these risk factors.

FMD slows down aging

In this randomized trial involving 100 participants, one part (group 1) followed a normal diet for 3 months, while the other (group 2) started FMD cycles. After 3 months, 43 participants from the first group followed the intervention using the FMD.

Also included were blood samples from participants in a second trial investigating the use of FMD for 4 consecutive months to reduce cardiometabolic risk factors, to measure its hypothetical effects on biological age, disease risk and life expectancy. Measurements of endothelial function and arterial compliance, blood pressure, serum lipids, glucose, cardiovascular biomarkers, body weight, body mass index (BMI), and body composition were made.

The results show that 3 cycles of the FMD diet reduced BMI and total body fat, including subcutaneous adipose tissue. Liver fat was also reduced, and very significantly (more than half) in participants in whom it was more than 5% before the intervention.

Aging leads to impaired production and function of immune cells, a phenomenon known as immunosenescence. In the study, 3 cycles of FMD promote rejuvenating effects on the immune system that could translate into a better response to infectious agents, a decreased risk of blood cancer and autoimmunity.

Finally, the researchers estimated the median biological age of participants who followed the FMD diet based on biological markers: it decreased by almost 2.5 years. This suggests that study participants who completed 3 cycles of FMD had profiles that appear biologically younger than at baseline.

Based on the simulation, the 20-year risk of heart disease mortality was reduced from 29.1% to 15.4%; the 20-year risk of cancer mortality was reduced from 26.0% to 18.9%; the risk of mortality from cerebrovascular disease over 20 years was reduced from 8.2% to 3.0%; and the 20-year risk of diabetes-related mortality was reduced from 2.6% to 0.6%.

These results suggest that annual cycles of FMD can modify life expectancy.

To learn more about fasting: The complete guide to fasting

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