Certain fasting diets can nearly double your risk of dying from cardiovascular disease, a shock new study has claimed.
The 16:8 diet where you eat all your food in an eight hour window and fast for the remaining 16 hours has been used by actress Jennifer Aniston, model Heidi Klum, and singer/actress Jennifer Lopez.
But researchers who studied 20,000 US adults on intermittent fasting, the majority of whom used the 16:8 plan, found it was not a good long-term option.
This style of eating is popular among those trying to lose weight, and studies have previously suggested it can improve blood pressure, blood glucose, and cholesterol levels.
But there is not much information on the long-term effects, which the research team wanted to investigate.
Results of their study, published in the American Heart Association Journal, found that those who limited their eating to eight hours a day were 91 per cent more likely to die from cardiovascular disease than those who ate across 12 or 16 hours.
Among people already living with a cardiovascular disease, eating for more than eight but less than 10 hours a day was associated with a 66 per cent higher risk of death from heart disease or stroke.
Meanwhile, people with cancer who ate for more than 16 hours a day were less likely to die from the disease.
Time-restricted eating did not reduce the risk of death from any cause.
Senior author Dr Victor Wenze Zhong, a professor at Shanghai Jiao Tong University in China, said: “Restricting daily eating time to a short period, such as eight 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 risk of death from cardiovascular disease or any other cause, are unknown.
“We were surprised to find in our study that people who followed an eight-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 to 16 hours per day, it may have long-term drawbacks.
“A shorter eating duration was not associated with living longer.”
Professor Zhong said the study should be of particular interest to those with existing heart conditions who are already predisposed to cardiovascular death.
“Our findings encourage a more cautious, personalised approach to dietary recommendations, ensuring they are aligned with an individual’s health status and the latest scientific evidence,” he explained.
The team also made sure to draw attention to the limitations of their study.
Prof Zhong highlighted that the study does not mean time-restricted eating causes cardiovascular death, while Dr Christoper Gardner, a professor at Stanford University in the US, pointed out that researchers relied on self-reported dietary information.
“This may be affected by participants’ memory or recall, and therefore may not accurately assess typical eating patterns,” he said.
Professor Gardner also suggested that future studies should consider how healthy the participants’ diets were.
“Without this information, it cannot be determined if nutrient density might be an alternate explanation to the findings that currently focus on the window of time for eating,” he said.
“It will also be critical to see a comparison of demographics and baseline characteristics across the groups that were classified into the different time-restricted eating windows.
“For example, was the group with the shortest time-restricted eating window unique compared to people who followed other eating schedules, in terms of weight, stress, traditional cardiometabolic risk factors, or other factors associated with adverse cardiovascular outcomes?
“This additional information will help to better understand the potential independent contribution of the short time-restricted eating pattern.”
The study analysed 20,000 US adults, with an average age of 49, over a median time period of eight years.
Approximately half of the participants were men and half were women.
Around 73 per cent of participants were non-Hispanic white adults, while 11 per cent were Hispanic, eight per cent were non-Hispanic black adults, and just under seven per cent were from another racial category.
People who practice a type of intermittent fasting popular with celebrities nearly double their risk of dying from cardiovascular disease, a new study claims.