Fasting Might Not Lead to Eternal Life—but It Could Make You Live Longer

New research shows that the religious practice of fasting has sound scientific reasoning behind it.

(Photo: Roberto A Sanchez/Getty Images)

Mar 9, 2015· 2 MIN READ
Padma Nagappan is a multimedia journalist who writes about the environment, renewable energy, sustainability, agriculture, and biotechnology.

There’s little overlap between the type of health advice proffered in any given Goop newsletter and the brand of asceticism practiced by the religiously devout. That is, save for fasting—which may help us experience something more like eternal life in this lifetime, increasing longevity in addition to trimming waistlines.

Researchers from the University of Florida did a three-year study in which they had 24 participants practice fasting (with one small meal in the afternoon) and feasting on alternate days for three weeks at a time. They found that the routine caused the gene related to antiaging in our cells to increase, which can lead to longevity. The study found that intermittent fasting decreased insulin levels for the participants, so it could help diabetics.

The research could inform new approaches to diet and nutrition, but its release in the midst of Lent is a reminder that religious fasts have been a tradition around the globe for thousands of years.

Buddhism, Christianity, Hinduism, Islam, Jainism, Judaism, and Taoism all advocate some form of fasting—from short periods to days, and even an entire month. Around the year 600, Lent involved six weeks of fasting for six days a week; today’s Catholics may opt to abstain from social media or cigarettes between Ash Wednesday and Easter. However, in light of the new research, modern adherents inclined to skip skipping meals might reevaluate their thinking.

“Part of the reason we did the study in the first place was to find out why fasting is thought to be good in religious practices,” said Douglas Bennion, coauthor of the study and an M.D.-Ph.D. candidate at UFL.

Just how many years could religious observance of fasting traditions—or a secular alternative—add to life? That isn’t quite clear. Previous studies done on mice and monkeys show that reducing calorie intake can improve health and life span by 25 percent. But as Bennion explained, fasting occasionally by skipping meals is becoming more popular because no one wants to be on a restricted diet for a lifetime—instead they can fast for short periods, gaining many of the same benefits.

The authors also wanted to find out if fasting could strengthen the body’s natural preventive processes that protect against future diseases.

“Our cells are amazing little machines that come built with the ability to encounter damage and repair themselves,” Bennion said. “But in repairing themselves, they can also set themselves up for future defensive measures, like cancer or diabetes or obesity. So if the cells see stress or damage, they set up a process to protect themselves in the future.”

When the body is under duress from, say, going without food for much of the day, small levels of oxidative stress—the inability of cells to detoxify oxygen quickly enough—can trigger protective pathways to form. And if the body is exposed to periodic stress, it learns to build a better response to it. In other words, fasting stresses out cells just enough to make them better at coping with that stress.

But most people undergoing a contemporary, nonreligious fast are hoping to lose weight, not condition their cells. The researchers wanted to keep fasting’s weight-loss and longevity benefits separate, so participants were asked to eat extra on the feasting day to keep their weight balanced.

“Studies of Ramadan fasters show that most don’t lose weight over the month of fasting because they feast every night, and we wanted to see if the protective benefit from fasting was present even without weight loss,” Bennion explained.

But many participants could not finish their regular meals on the feasting day after having just one small meal the previous day; their bodies were becoming accustomed to the new habit.

Another interesting finding from the study was that antioxidant supplements prevented cells from setting up this longevity response. When participants repeated the three-week fasts with vitamin A and C pills, the benefits they saw in the earlier period of fasting disappeared. This was in line with research that indicates that flooding the system with supplemental antioxidants may counteract the effects of fasting or exercise.

Which suggests that perhaps ancient Christians—and Muslims and Hindus and Jews, and the forebearers of just about every other religion—were onto something with their fasting traditions, even if they didn’t know about the oxidative stress from antioxidants.

Bennion thinks this is just the beginning of research giving ancient rites a scientific underpinning. “Science will continue to show there’s good scientific reasons behind many religious practices,” he said.