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Intermittent fasting involves alternating between eating and fasting for specific periods of time. For example, a common approach is to eat within eight hours each day, says Krista Varady, a professor of nutrition at the University of Illinois at Chicago.

Some short-term studies suggest this eating style may lead to some weight loss, lower blood pressure and improve blood sugar control in certain people, she said.

But Victor Wenze Zhong, lead author of the new study and an epidemiologist at Shanghai Jiao Tong University School of Medicine in China, said the longest intermittent fasting trial lasted only a year. His aim, he said, is to focus on long-term health.

research

The new study included more than 20,000 U.S. adults. Participants completed two questionnaires less than two weeks apart about their meal times the previous day. The researchers then calculated the participants’ average eating window and assumed that was their typical schedule for the rest of the study, Dr. Zhong said. Participants were followed for an average of eight years.

During that period, participants who restricted their eating to eight hours a day were 91 percent more likely to die from cardiovascular disease than those who ate in a 12- to 16-hour window, the researchers reported. .

However, there were only 414 participants in the eight-hour eating group, Dr. Zhong said. And they tended to be younger and less educated. They have low incomes and less access to food. more likely to smoke than other participants.

The researchers considered these factors in their analysis, Dr. Zhong said. However, the study did not show that this dietary style caused deaths from cardiovascular disease, only that the two were linked.

limit

The study has not been published or peer-reviewed, making it difficult to fully evaluate it, Dr. Varady said.

A “major limitation” was that only two dietary questionnaires were used to accurately represent people’s typical eating patterns, Dr Varady said. And the study didn’t seem to assess what types of food people ate.

Dr. Darish Mozaffarian, a cardiologist and professor at Tufts University School of Medicine, called the study “very problematic.” He said the eight-hour eating group likely included many people who were very busy or faced other challenges that forced them to skip meals or eat irregularly. It is said that there is a sex.

Satchidananda Panda, a professor at the Salk Institute, said the group may have included people who were already in poor health, such as people with eating disorders or illnesses that reduce their appetite. For a San Diego biological study that said it may have led to people eating for less time as a result.

And if intermittent fasting is truly harmful, it’s not clear why. Dr. Zhong said his study was not designed to answer that question.

what’s next

Further research is needed to assess the long-term health effects of intermittent fasting, Dr. Zhong said.

Dr. Pam Taub, a cardiologist at the University of California, San Diego, says intermittent fasting isn’t for everyone. However, many of her patients enjoy benefits such as lower cholesterol levels.

Patients are now “confused and scared” by the headlines they are reading, Dr. Taub said. But she doesn’t recommend changing anything based on this study, she says, adding that she should always consult her doctor before making any changes to her diet or lifestyle.