In a study of more thanÂ 4,500 men and women, people who fasted were 39% less likely to be diagnosed with coronary artery disease than those who didn't fast. Coronary artery disease was defined as having at least 70% narrowing or blockage in at least one coronary artery.
Though more than 90% of the people studied were Mormons, the findings held true even in those who had a different religious preference, says Benjamin D. Horne, PhD, director of cardiovascular and genetic epidemiology at Intermountain Medical Center in Salt Lake City.
The researchers did not put any time frame on fasting, but Horne notes that "among [Mormons], religious teachings involve fasting on the first Sunday of every month for 24 hours."
The findings were reported at the American Heart Association's Scientific Sessions 2007.
Fasting and Heart Risk
In the 1970s, scientists recognized that Mormons in Utah are less likely to die of heart disease than other Americans.Â
Their prohibition against tobacco is usually credited for the health benefit, Horne says, but the new study shows fasting plays a role, too.
The analysis took into account the prohibition against smoking as well as other religious teachings that can affect heart disease risk, including avoiding tea, coffee, and alcohol; observing a weekly day of rest; attending worship services; and donating to charity.
Horne tells WebMD that while fasting seemed to benefit "the handful of people with diabetes studied, they could run into trouble [with blood sugar levels] if they start skipping meals."
He says that fasting could be a marker for eating less in general. Very low-calorie diets have been shown to extend longevity in several studies.
Or fasting itself may lower the risk of heart disease through some undiscovered biological mechanism, he says.
Fasting May Not Be Right for Everyone
AHA past president Sidney Smith, MD, a heart doctor at the University of North Carolina in Chapel Hill, says he would be very reluctant to make sweeping recommendations about the benefits of fasting without more information about the dietary practices of the people studied.
"It's not clear how other populations [that don't follow the same strict practices as Mormons with regard to eating, smoking, and drinking] would handle fasting. It could even be harmful," Smith tells WebMD.