The safety of intermittent fasting – a popular strategy to lose weight by limiting food intake to certain times – was called into question by a surprise finding from research presented at the 2024 American Heart Association’s (AHA) Lifestyle Scientific Sessions meeting in Chicago, United States.
Limiting mealtimes to a period of just eight hours a day was linked to a 91% increase in risk of death from heart disease in the study, which was released on March 18.
The AHA published only an abstract, leaving scientists speculating about details of the study protocol.
The study was reviewed by other experts prior to its release, according to the association.
Lifestyle interventions aimed at weight loss have come under scrutiny as a new generation of drugs help people shed pounds.
Some doctors questioned the study’s findings, saying they could have been skewed by differences – such as underlying heart health – between the fasting patients and the comparison group, whose members consumed food over a daily period of 12 to 16 hours.
“Time-restricted eating is popular as a means of reducing calorie intake,” said United Kingdom’s University of Oxford emeritus professor of human metabolism Dr Keith Frayn in a statement to the UK Science Media Center.
“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.”
The researchers, led by China’s Shanghai Jiao Tong University School of Medicine Department of Epidemiology and Biostatistics chair Professor Dr Victor Zhong, analysed data from about 20,000 adults included in the US Centers for Disease Control and Prevent-ion’s (CDC) National Health and Nutrition Examination Survey.
The study looked at answers to questionnaires, along with death data, from 2003 through 2019.
Because it relied in part on forms that required patients to recall what they ate over two days, scientists said there was room for potential inaccuracies.
About half of the patients were men and the mean age was 48 years.
It wasn’t clear how long the patients kept up the intermittent fasting.
Prof Zhong did not immediately reply to an email seeking comment by the time of publication. – By Marthe Fourcade/Bloomberg News/Tribune News Service