A diet replicating some of the effects of fasting may not only allow you to shed pounds, but it could improve your memory and lengthen your life, researchers suggest.
A study led by the University of Southern California showed that older mice put on four-day cycles featuring a diet mimicking fasting not only lost belly fat but showed elevated numbers of progenitor cells and stem cells within several of their organs, including their brains.
The mouse study follows earlier research using yeast cells that allowed the researchers to identify the biological mechanisms fasting can trigger at the cellular level.
Additionally, a pilot study with humans suggests the mechanisms seen in the yeast and mouse studies are applicable in humans, the researchers report in the journal Cell Metabolism.
In that human trial, volunteers put on cycles of a fasting mimicking diet (FMD) once a month for five days displayed reduced risk factors and biomarkers for aging, cardiovascular disease, diabetes and cancer, while experiencing no major adverse side effects, researchers wrote.
"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," says study leader Valter Longo, a biogerontology professor at the USC Davis School of Gerontology. "I've personally tried both, and the fasting mimicking diet is a lot easier and also a lot safer."
In the diet, the caloric intake of study volunteers was reduced between 34 and 54 percent of their usual intake, with a precise formulation of carbohydrates, proteins, fats and nutrients.
One result was a decrease in the amount of the hormone IGF-1, which humans need during their developmental years to grow, but which has been identified as a promoter of the aging process and has been associated with susceptibility to cancer later in life.
While not in the fasting diet cycle, the study volunteers returned to their normal eating habits for 25 days each month. They were not asked to change their usual diet — be it good or bad — and still showed positive results from the fasting diet cycles, Longo says.
"It's about reprogramming the body so it enters a slower aging mode, but also rejuvenating it through stem cell-based regeneration," he says. "It's not a typical diet because it isn't something you need to stay on."
Longo says he believes most people could see a benefit in doing the FMD every three to six months, depending on their level of obesity and general health status.
He did caution against attempting a fasting mimicking diet without a consultation with a doctor first and arranging for medical supervision during the diet cycle process.
"Not everyone is healthy enough to fast for five days, and the health consequences can be severe for a few who do it improperly," he warns.