A recent study suggested that intermittent fasting could be linked to a 91% increased risk of cardiovascular disease, but experts are skeptical of the results.
The study was presented at the American Heart Association's preliminary research meeting on March 18. It analyzed survey data from more than 20,000 adults who followed an 8-hour time-restricted eating schedule, also known as intermittent fasting, and compared them to people who ate across 12 to 16 hours per day. The researchers reviewed information about the dietary patterns of participants in the annual 2003 to 2018 National Health and Nutrition Examination Survey and compared it to the CDC's National Death Index data on people who died between 2003 and December 2019.
The study found people who restricted their eating window to less than 8 hours a day had a 91% higher risk of death due to cardiovascular disease and that time-restricted eating did not reduce the overall risk of death from any cause.
"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," Victor Wenze Zhong, PhD, lead author of the new study and an epidemiologist at Shanghai Jiao Tong University School of Medicine in China, said in an AHA release.
However, experts are skeptical of the findings that have made headlines this week.
For one, the research has not yet been published in a peer-reviewed journal, and the longest intermittent fasting trial lasted only one year, Dr. Zhong told the New York Times.
The surveys also had limitations, with participants completing two questionnaires less than two weeks apart that asked about what time they ate on the previous day. Researchers calculated the participants' average eating windows and assumed that was their typical schedule. The participants were followed for an average of eight years, and only 414 people were in the eight-hour eating group, Dr. Zhong said. These people tended to be younger, less educated and wealthy, more likely to smoke and have less access. The study also did not show that this style of eating caused deaths from cardiovascular disease, only that the two were linked.
Previous research has found that intermittent fasting improves cardiometabolic health measures such as blood pressure, blood glucose and cholesterol levels.