It’s a dieting trend endorsed by everyone from Hollywood A-listers to the current British Prime Minister.
But new research suggests intermittent fasting could in fact be damaging to long-term health.
Those who only eat during eight hours of the day are at almost twice the risk of heart attack and stroke later in life, a study found.
Experts said it showed why people should be cautious when adopting trendy diets before the effects are fully known.
This study suggests that to get the full benefits of fasting, someone may need to go without food for 72 hours – instead relying on only water
Time-restricted eating, a type of intermittent fasting, involves limiting the hours for eating to between four and 12 hours over a 24-hour period.
It has gained popularity in recent years with the likes of British PM Rishi Sunak, Elon Musk and actress Jennifer Aniston suggesting it helps them to stay trim.
Previous studies have linked time-restricted eating to improvements across several cardiometabolic health measures, such as blood pressure, blood glucose and cholesterol levels.
Now early research involved 20,000 adults found those who followed a time-restricted eating plan were 91 per cent more likely to die from cardiovascular disease.
The trendy dieting schedule did not reduce participants chances of death from any cause, according to the findings being presented at the American Heart Association’s Lifestyle Scientific Sessions 2024 conference this week.
Researchers reviewed information about dietary patterns from annual health surveys between 2003-2018 and compared it to death data over the same period.
Many who follow a time-restricted eating diet follow a 16:8 eating schedule, where they eat all their foods in an 8-hour window and fast for the remaining 16 hours each day.
They found this was associated with a greater risks of dying from cardiovascular disease when compared to people eating during 12- and 16-hour windows.
Those with existing heart disease or cancer were particularly at risk, they noted.
Professor Victor Wenze Zhong, of the Shanghai Jiao Tong University School of Medicine, China, said: ‘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.’
The observational research did not consider other possible contributory factors, such as participants weight and cholesterol, at the start of the study or over the eight-year follow-up period.
It relied on self-reported dietary information and other lifestyle factors, such as smoking and exercise levels were not included in the analysis.
Commenting on the research, Keith Frayn, Emeritus Professor of Human Metabolism at Oxford University, said: ‘Time-restricted eating is popular as a means of reducing calorie intake, although its proponents claim other benefits such as “ramping up metabolism”.
‘This work is very important in showing that we need long-term studies on the effects of this practice.
‘But this abstract leaves many questions unanswered, and further research will be needed. ‘
Tom Sanders, Professor emeritus of Nutrition and Dietetics at King’s College London, said although popular, there is little evidence to show fasting benefits weight loss or weight maintenance.
He added: ‘We know from previous existing evidence that it is probably better to spread food intake out throughout the day – small but often – rather than consume large meals over a shorter period.
‘This is because large increases in blood fats and glucose result after big meals.’
