People who regularly fast seem to be less likely to experience severe complications from COVID-19, according to a new study.

Intermountain Healthcare researchers found that COVID-19 patients who practiced regular intermittent fasting, consuming water only during the fast, had a lower risk of hospitalization or death compared to those with the virus who didn’t fast.

“Intermittent fasting has already shown to lower inflammation and improve cardiovascular health,” Dr. Benjamin Horne said during a press conference Wednesday. Horne is the director of cardiovascular and genetic epidemiology at Intermountain Healthcare and principal investigator of the study. “In this study, we’re finding additional benefits when it comes to battling an infection of COVID-19 patients who have been fasting for decades.”

Horne said many of the study participants have regularly been fasting at least once a month for 40 years or more. Researchers were able to closely study this specific group of long-term fasters because a large portion are members of The Church of Jesus Christ of Latter-day Saints and practice intermittent fasting the first Sunday of every month.

“Intermittent fasting has shown to have many health benefits, including lowering the risk for cardiovascular disease, heart failure and diabetes,” Horne said. “Fasting acts directly against what SARS CoV-2 is trying to do.”

Horne said while further study is needed to understand the connection, the outcomes are most likely due to a plethora of ways fasting affects the body. Fasting, he said, reduces inflammation in the body. Hyperinflammation is associated with poor COVID-19 outcomes. After 12 to 14 hours of fasting, Horne said the body switches from using glucose in the blood to ketones, including linoleic acid. Ketones are substances the body makes when you don’t get enough blood sugar (glucose).

“There’s a pocket on the surface of SARS-CoV-2 that linoleic acid fits into and can make the virus less able to attach to other cells,” Horne said.

In addition, the body’s recycling system, called autophagy, helps the body destroy and recycle damaged and infected cells.

Horne said there are certain groups of people who should talk in depth with their physician before considering a fast. They include pregnant and lactating women, and people with diabetes and heart and kidney disease. Fasting is not recommended for young children, people with hypoglycemia and the elderly who are frail.

“You still need to get vaccinated and boosted,” Horne said. “Intermittent fasting should be used as a complementary method and not a substitute.”

The study, published this week in BMJ Nutrition, Prevention & Health, identified patients enrolled in the INSPIRE registry, a voluntary health registry at Intermountain Healthcare. Patients had tested positive for COVID-19 between march 2020 and February 2021, before vaccines were widely available.

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