A new study has questioned the supposed health benefits of intermittent fasting, a popular diet often praised by celebrities and health gurus alike.
Intermittent fasting is a well-known practice in which you eat your entire meal in an eight-hour period and fast for the remaining 16 hours of the day. However, an American Heart Association study published Monday, March 18, found that limiting mealtimes to just eight hours a day was linked to a 91 percent increase in the risk of death from heart disease.
The researchers, led by Dr. Victor Zhong of Shanghai Jiao Tong University School of Medicine, analyzed approximately 20,000 adults in the United States with an average age of 49 years who had followed intermittent fasting, also known as plan 16: 8.
According to the study, which was presented at the AHA Epidemiology and Prevention conference in Chicago, Illinois, those who limited their eating to eight hours a day were 91 percent more likely to die from cardiovascular disease than those who ate for 12 or 16 hours. . Among participants with existing cardiovascular disease, eating eight to 10 hours a day was also associated with a 66 percent increased risk of death from heart disease or stroke.
Meanwhile, people with cancer who ate more than 16 hours a day were less likely to die from the disease. The researchers also found that time-restricted eating did not reduce the overall risk of death from any cause.
“Restricting daily eating time to a short period, such as eight hours a day, has gained popularity in recent years as a way to lose weight and improve heart health,” said the study's lead author, Dr. Zhong. . “However, the long-term effects of time-restricted feeding are unknown, including the risk of death from any cause or cardiovascular disease.”
“We were surprised to find that people who followed an eight-hour, time-restricted eating schedule were more likely to die from cardiovascular disease. Although this type of diet has been popular due to its potential short-term benefits, our research clearly shows that, compared to a typical eating time window of 12 to 16 hours per day, a shorter eating duration is not associated with a longer life. ” he said.
The study analyzed data from participants in the 2003-2018 National Health and Nutrition Examination Surveys and compared it to the Centers for Disease Control and Prevention's National Death Index database of people who died. in the US from 2003 to December 2019.
The researchers acknowledged that the study's findings were limited because it was based on self-reported dietary information and did not focus on other factors that may play a role in participants' health.
“Overall, this study suggests that time-restricted eating may have short-term benefits but long-term adverse effects. When the study is presented in its entirety, it will be interesting and useful to know more details of the analysis,” said Dr. Christopher D Gardner, Rehnborg Farquhar Professor of Medicine at Stanford University.
“One of those details has to do with the nutrient quality of the typical diets of different subsets of participants. Without this information, it cannot be determined whether nutrient density could be an alternative explanation to findings that currently focus on the eating window. Secondly, it is necessary to emphasize that the categorization into the different time-restricted feeding windows was determined on the basis of only two days of dietary intake,” he said.
Approximately half of the participants were men and the other half were women. About 73 percent of the participants were non-Hispanic white adults, while 11 percent were Hispanic. Eight percent of participants were non-Hispanic black adults and nearly seven percent of adults identified as another race.
“It will also be critical to see a comparison of demographics and baseline characteristics between the groups that were classified into the different time-restricted feeding windows,” Gardner added. “For example, was the group with the shorter restricted eating window unique compared to people who followed other eating schedules, in terms of weight, stress, traditional cardiometabolic risk factors, or other factors associated with adverse cardiovascular outcomes?
“This additional information will help better understand the possible independent contribution of the short-duration dietary pattern reported in this interesting and provocative summary.”
In June 2023, a similar study looked at the weight loss results of adults with obesity who participated in intermittent fasting, compared to traditional calorie counting. The results, which were published in the journal Annals of Internal Medicine, found that those who ate over eight hours had better insulin sensitivity compared to those in the control group who ate their calories at any time for 10 or more hours. up to date. .
