Intermittent fasting, known for its potential to reduce weight and lower blood pressure, may pose a risk to cardiovascular health over extended periods. A study from Shanghai Jiao Tong University School of Medicine presented at the American Heart Association’s sessions found that individuals who fasted for less than eight hours daily had a significantly increased risk of cardiovascular death over an eight-year period. This contrasts with those who had a longer eating window of 12 to 16 hours.
This new research, still awaiting peer review, delves into the relationship between time-restricted eating and cardiovascular mortality. It’s based on data from the National Health and Nutrition Examination Survey and covers responses from approximately 20,000 adults.
The study’s co-author, Victor Wenze Zhong, advises caution with long-term intermittent fasting, noting that while short-term practice may improve weight and heart health, extended fasting needs more scrutiny.
Intermittent fasting regimens vary, from daily time-restricted eating to the “5:2 diet,” which involves significant calorie reduction on two nonconsecutive days each week. The concern arises from the association of these fasting methods with decreased lean muscle mass, which has been linked to higher cardiovascular risk.
Experts outside the study suggest various theories for these findings. Dr. Benjamin Horne from Intermountain Health points to increased stress hormones during fasting, potentially raising short-term heart risks. Yet, he still sees fasting benefits in the long term.
Despite its popularity and anecdotal success, much of the early research on intermittent fasting involved animals, with human trials only emerging in recent years.
The study’s reliance on self-reported data and its limited scope draws criticism from some experts, like Dr. Pam Taub of UC San Diego Health, who argues that the benefits seen in her patients warrant continued fasting practices. However, Penny Kris-Etherton, a nutrition expert at Penn State University, suggests a cautious approach until more information is available.
The research underscores the need for a balanced perspective on intermittent fasting, considering both its potential benefits and emerging concerns about long-term cardiovascular risks.