Intermittent fasting, a popular dieting technique embraced by many, is being called into question after a recent study suggests that an 8-hour time-restricted eating pattern is linked to a higher risk of death from heart disease.

The intermittent fasting technique involves alternating cycles of fasting and eating, with time-restricted eating being one frequently practiced approach. This eating pattern includes methods such as the 16/8 technique (fasting for 16 hours and eating within an eight-hour window) or the 14/10 method (a 14-hour fast followed by a 10-hour eating period). Additionally, there are other techniques, such as alternate-day fasting, twice-weekly fasting, and a once-weekly 24-hour fast.

"Restricting daily eating time to a short period, such as 8 hours per day, has gained popularity in recent years as a way to lose weight and improve heart health. However, the long-term health effects of time-restricted eating, including the risk of death from any cause or cardiovascular disease, are unknown," said senior study author Victor Wenze Zhong from the Shanghai Jiao Tong University School of Medicine in Shanghai, China.

In the latest study, researchers investigated the potential long-term health impact of following an 8-hour time-restricted eating plan by evaluating over 20,000 adults with an average age of 49 years.

According to the results of the preliminary research presented at the American Heart Association's Epidemiology and Prevention-Lifestyle and Cardiometabolic Scientific Sessions 2024, people who followed an 8-hour time-restricted eating schedule had a 91% higher risk of cardiovascular death.

The researchers noted an increased risk of cardiovascular death also in people living with heart disease or cancer. For people already diagnosed with cardiovascular disease, having an eating duration of at least 8 hours but less than 10 hours per day was linked to a 66% increased risk of death from heart disease or stroke.

The study also revealed that limiting food intake to less than 8 hours per day was not associated with improved longevity when compared to the standard schedule of eating across 12-16 hours per day.

At the same time, an eating duration of more than 16 hours per day was associated with a lower risk of cancer mortality among people with cancer.

"We were surprised to find that people who followed an 8-hour, time-restricted eating schedule were more likely to die from cardiovascular disease. Even though this type of diet has been popular due to its potential short-term benefits, our research clearly shows that, compared with a typical eating time range of 12-16 hours per day, a shorter eating duration was not associated with living longer," Zhong said.

"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. 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.

The study does not indicate that time-restricted eating caused cardiovascular death but identifies an association between an 8-hour eating window and cardiovascular death.

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