A surprising discovery presented at a medical conference has cast doubt on the safety of intermittent fasting, a widely adopted weight loss method that involves restricting food consumption to specific periods.
The study, released in Chicago on Monday, found a concerning link between restricting meal times to just eight hours a day and a 91% increase in the risk of death from heart disease. However, the American Heart Association only published an abstract, leading scientists to speculate about the study’s protocol details. Nonetheless, the AHA assures that the study underwent peer review by other experts before its release.
As a new generation of drugs assists in weight loss, lifestyle interventions targeting weight reduction are facing scrutiny. Some doctors have raised concerns about the study’s findings, suggesting that differences, such as variances in underlying heart health, between the fasting patients and the comparison group (whose members consumed food over a daily period of 12 to 16 hours) could have skewed the results.
“Time-restricted eating is popular as a means of reducing calorie intake,” remarked Keith Frayn, emeritus professor of human metabolism at the University of Oxford, 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.”
Led by Victor Zhong of the Shanghai Jiao Tong University School of Medicine, the researchers analyzed data from approximately 20,000 adults included in the US Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey.
The study examined responses to questionnaires alongside death data spanning from 2003 to 2019. However, since it partially relied on forms where patients had to recall their food intake over two days, scientists acknowledged the possibility of inaccuracies. Approximately half of the patients were men, with a mean age of 48.
The duration of intermittent fasting among the patients was not explicitly stated. The abstract was presented at the AHA’s Lifestyle Scientific Sessions meeting in Chicago.