Dave Benton* has been in bed for three days. He is not sick. He does not have the flu. His bedridden state is self-inflicted. 

He is fasting. 

Fasting, or intentionally abstaining from food and drink, is often practiced as part of religious rituals, and Benton is performing his own yearly ritual the week before his birthday.  

Benton spoke to me about his fasts as we sat on the back porch of his Bellingham home. The day was sunny and warm, a rarity for winter in northwest Washington. Benton turned 70 this year and has been practicing his yearly fast for more than five decades, having completed the first one when he was just 19. His fasts typically range from six to 10 days and always take place around his January birthday.  

Benton is energetic and slight of frame, though does not appear undernourished. He suffers only from chronic back pain linked to years of construction work. Could his lack of chronic diseases, increasingly common in the United States, be a result of his ritual? Scientists are beginning to answer this question with growing confidence. 

Their answer? A preliminary yes. 

Though fasting research began only decades ago, people have practiced it for centuries. Ancient civilizations believed fasting people could more easily convene with the gods. Muslims observe a period of fasting during Ramadan and Jews fast on Yom Kippur, a day of atonement. Its use in medicine, however, has more recent and tenuous roots. Yet a growing body of research suggests a type of fasting called intermittent fasting could substantially improve health.  

Intermittent fasting (IF) consists of fasting for short periods of time throughout the day or week. The two main types are daily time-restricted feeding, in which eating is confined to a six- to eight-hour period of the day, or 5:2 fasting in which calorie intake is drastically reduced two days a week. Both methods flip a “metabolic switch,” whereby the body stops metabolizing glucose and begins breaking down fat cells into ketone bodies to be used for energy. 

This metabolic switch, according to Johns Hopkins neuroscientist Mark Mattson, is what confers IF’s benefits. Ketone bodies not only provide energy to the body but also “regulate the expression and activity of many proteins and molecules that are known to influence health and aging,” writes Mattson in a 2019 article published in The New England Journal of Medicine. The review analyzed animal and human IF studies in order to illuminate fasting’s numerous health benefits. According to Mattson, the evidence suggests that IF could treat and prevent chronic diseases such as type II diabetes, obesity, cancer, and neurodegenerative disorders like Alzheimer’s. 

This evidence was scarce in 1969 when Dave Benton fasted for the first time. He explains, however, that he started fasting to avoid health problems that afflicted his family. “Both of my parents always struggled with weight,” he says, a hint of seriousness creeping into his laid-back manner of speaking.  

“My father died when I was 13 of a heart attack. My mother battled with cancer for decades.” While attending the University of Oregon, he found a pamphlet on colon health that suggested fasting could improve overall health, so he tried it. “It was just like an adventure,” he says, reflecting on his first fast. 

These days, his fasts are less adventurous and more regimented. He forgoes all responsibilities for the week and stays in bed for the first few days, sleeping as much as possible. Usually by the fourth day his fatigue dissipates, and he gets out of bed. He keeps it low energy — reading, going for walks, watching Netflix. Finally, when he feels he has achieved a fresh state of mental clarity and rejuvenation, typically six to 10 days later, he ends his fast. 

However, between jobs, families, and social commitments, relinquishing responsibilities for a whole week is likely impossible for the average person. That’s where IF comes in. While long periods of fasting may be unrealistic, IF is more attainable. And as research for its health-enhancing benefits becomes more robust, some doctors, like Libby Abbas, are beginning to use it to treat patients.  

Abbas has been practicing family medicine for five years in rural Iowa and, for the past year, has been prescribing IF to overweight patients. She noticed that many conditions she treated were preventable with diet and exercise, but her patients had a hard time adhering to healthy regimens. She began searching for alternatives and came across IF. 

Based on the research and her patients’ successes, she sees IF as a powerful practice that enables people to take control of their health. One of her patients lost weight for the first time in twenty years after adopting IF. According to Abbas, she felt “empowered that she’s actually able to make positive change and be in control of her body.” 

Abbas has also seen diabetes and prediabetes cured in some patients who practice IF in conjunction with medication. Unlike diets, which often leave people feeling frustrated and defeated, IF has motivated her patients to build and maintain a healthy lifestyle. Her patients find IF easier to adopt than diets and exercise, too.  

“A lot of really busy people have a hard time finding time for exercise and some of these other things,” Abbas says, “but fasting is fast, and it’s easy, and it actually saves you time.” 

Still, IF doesn’t work for all patients, and others are unable to adopt the lifestyle changes it requires. But Abbas and Mattson are convinced that IF is a promising solution to many of America’s chronic health problems. 

Dave Benton agrees. The night before he breaks his fast, he eats a single banana. The next day, his birthday, he treats himself to “a simple salad, a piece of really good bread, and a glass of good chardonnay.” 

 *Not his real name.