Intermittent fasting has gained traction as a popular approach to weight loss, yet recent research indicates it may elevate the risk of mortality due to heart disease.

A study by the American Heart Association examined over 20,000 adults, revealing that individuals adhering to an eight-hour time-restricted eating plan, a form of intermittent fasting, faced a 91% heightened risk of death from heart disease compared to those spreading their meals over 12 to 16 hours daily.

This dietary method alternates periods of fasting with periods of eating and includes variations such as fasting every other day, limiting eating to two days a week, or eating within a restricted timeframe each day. Among these, time-restricted eating—where all meals are consumed within a 10-12 hour period or even less—remains the most favored.

While previous research from Johns Hopkins Medicine has shown that intermittent fasting improves health measures, such as blood pressure, blood glucose, and cholesterol levels, the AHA study showed that there was an increased risk of death from heart disease among people who were diagnosed with heart disease or cancer.

Among people who had heart disease, an eating duration of no less than eight hours but less than 10 hours daily was also associated with a 66% higher risk of death from heart disease or stroke.

“It’s crucial for patients, particularly those with existing heart conditions or cancer, to be aware of the association between an 8-hour eating window and increased risk of cardiovascular death,” senior study author Dr. Victor Wenze Zhong said. “Our study’s findings encourage a more cautious, personalized approach to dietary recommendations, ensuring that they are aligned with an individual’s health status and the latest scientific evidence.”

Zhong added that although a link between eight-hour, time-restricted intermittent fasting and death from heart disease exists, it does not suggest that time-restricted eating caused death from the disease.