Fasting has been practiced since ancient times as a cleansing process, often accompanied by prayer and periods of seclusion. Famous enlightened historical figures like Jesus or Buddha are prime examples of such ascetic practice, with the latter almost raising fasting to a form of art.But as a new study has shown, fasting needs not be merely associated with spiritualism or religion – it could very well be a great tool to improve your health.

Several studies have documented the benefits of fasting, but on the other hand how many of us could go through such excruciating torments, living on water alone for days at a time (some Buddhist monks do it for weeks). After all, low calorie diets are hard enough, let alone not eating altogether. A new study, however, suggests that there might be a way to trick your body it’s in fasting mode, and thus reap the benefits, without actually going overboard.



University of Southern California aging researcher Valter Long wanted to see what happened to animals and humans alike if they’d been fed on a fasting-mimicking diet for a couple of days every month. Long and colleagues performed three sets of experiments: on yeast, mice and ultimately humans.

When the yeast was fed with an alternating diet which ranged from a nutrient medium to fasting, the yeast lived longer than the control. Moving on to mice, the researchers offered the rodents a low-protein, low-calorie meal two for a 4-day periods each month. The rest of the month they could eat as much as they pleased. The team found that the fasting mice outlived their control brethren by three months, which is quite a lot considering the lifespan of a mouse. The mice which fed on the fasting-mimicking diet shed fat and were 45% less likely to fall victim to cancer,  blood sugar fell by 40% and the amount of insulin in the blood was 90% lower. This suggests that the fasting helped the mice be less prone to cancer, cardiovascular diseases and diabetes.

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The most exciting find was that the low-calorie diet also improved tissue replenishment. Namely, regeneration of the liver was quicker in the fasting animals, and the balance of different types of cells in their blood was more youthful, as echoed by the increase stem cell numbers.

In the experiment on humans, 19 participants were given a box that included powdered soups, nut bars and chips. It provided about 1,090 calories on the first day and about 725 calories on Days 2 through 5. The meals were proportional on a level to the meals served to the fasting mice. Just to get an idea, this is what 200 calories look like. In total, the participants went through only three rounds (5 days every month for three months) of alternating between a fasting-mimicking diet and business as usual.

When compared with the control group, also randomized and comprising 19 participants, the fasting humans showed improved physical condition, less body fat and blood glucose, and lower levels of proteins associated with cardiovascular diseases. Like in the case of the mice, the fasting humans also had more stem cells in their blood. “We think that what the fasting mimicking diet does is rejuvenate,” Longo says. “Everything is getting a little younger and it goes back to working much better,” he added. Longo and colleagues’ findings appeared in the journal Cell Metabolism.

“We try to make it as close as possible to something that looks like normal food,” Longo said, adding that 95% of the dieters stuck with the plan — a success rate that surprised the researchers.

“I think people noticed a lot of results, and that motivated them to come back,” he said.

Longo is now almost ready to wrap up another study featuring 80 to 90 participants and plans on meeting FDA officials to discusses whether the diet might be appropriate for people with illnesses like cancer. Doctors might soon prescribing such diets to patients. However, that doesn’t mean you should try it at home by yourself without any supervision. It can be dangerous, depending on your health history and physical condition. “This is actually a strong intervention,” he warned.