Fasting has been a part of human culture from prehistoric times. Whether it was a seasonal fluctuation in the availability of food, a ritual fast or simply a modern cleansing fast, many human beings have seen regular restrictions in their caloric input for extended periods of time. That’s why it’s not too surprising that a new study by researchers at the University of Southern California shows that fasting (or near-fasting) can lead to significant health benefits.
In the new research, USC professor Valter Longo and his colleagues proved that cycles of a four-day low-calorie diet that mimics fasting notably reduced visceral belly fat and increased the number of progenitor and stem cells in the organs of older mice. Of note, the brains of the mice saw significant neural regeneration and clearly improved learning and memory.
This research involving mice was part of a three-part study on the impact of periodic fasting that experimented on yeast, mice and humans. The study was published in the academic journal Cell Metabolism on June 18th.
More on new fasting study
The initial experiments on simple yeast allowed Longo to determine the biological mechanisms fasting triggers at a cellular level. The study of mice offered further details about fasting’s lifelong effects in mammals. Perhaps most importantly, the pilot study in humans provided strong confirmatory evidence that the mouse and yeast studies also applied to humans.
Fasts twice a month that lasted four days beginning at middle age increased life span, cut cancer rates, improved the immune system, reduced inflammatory diseases, slowed down bone mineral density loss and notably improved the cognitive abilities of older mice in the study. Also of interest, the total monthly calorie intake for the minimal diet fasting and control diet groups was the same, making it clear the positive effects did not relate to an overall dietary restriction.
In the human trial, a very low calorie but nutritious diet given to 19 subjects once a month for five days cut risk factors and biomarkers for aging, diabetes, cardiovascular disease and cancer.
The very low calorie (fasting-like) diet reduced caloric intake down to 34 to 54 percent of normal, but included required proteins, carbohydrates, fats and micronutrients.
Statement from lead researcher
“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,” Valter Longo, Edna M. Jones Professor of Biogerontology at the USC Davis School of Gerontology and director of the USC Longevity Institute, explained. “I’ve personally tried both, and the fasting mimicking diet is a lot easier and also a lot safer.”