Periodically adopting a diet that mimics the effects of fasting may boost health in a wide variety of ways, new research shows.
In a new study, Valter Longo and his colleagues showed that cycles of a four-day low-calorie diet that mimics fasting (FMD) cut visceral belly fat and elevated the number of progenitor and stem cells in several organs of old mice—including the brain, where it boosted neural regeneration and improved learning and memory.
The mouse tests were part of a three-tiered study on periodic fasting’s effects—testing yeast, mice, and humans—published in Cell Metabolism.
Mice, which have relatively short life spans, provided details about fasting’s lifelong effects. Yeast, which are simpler organisms, allowed Longo to uncover the biological mechanisms that fasting triggers at a cellular level. And a pilot study in humans found evidence that the mouse and yeast studies were applicable to humans.
Bimonthly cycles that lasted four days of an FMD that started at middle age extended life span, reduced the incidence of cancer, boosted the immune system, reduced inflammatory diseases, slowed bone-mineral-density loss, and improved the cognitive abilities of older mice tracked in the study.
The total monthly calorie intake was the same for the FMD and control diet groups, indicating that the effects were not the result of an overall dietary restriction.
Slashing Calories
In a pilot human trial, three cycles of a similar diet given to 19 subjects once a month for five days decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease, and cancer with no major adverse side effects, according to Longo.
“Strict fasting is hard for people to stick to, and it can also be dangerous, so we developed a complex diet that triggers the same effects in the body,” said Longo, professor of biogerontology at the University of Southern California Davis School of Gerontology and director of the USC Longevity Institute.
“I’ve personally tried both, and the fasting-mimicking diet is a lot easier and also a lot safer.”
The diet slashed the individual’s caloric intake down to 34 to 54 percent of normal, with a specific composition of proteins, carbohydrates, fats, and micronutrients. It decreased amounts of the hormone IGF-I, which is required during development to grow, but it is a promoter of aging and has been linked to cancer susceptibility.
It also increased the amount of the hormone IGFBP- and reduced biomarkers or risk factors linked to diabetes and cardiovascular disease, including glucose, trunk fat, and C-reactive protein, without negatively affecting muscle and bone mass.
