Past research has shown that intermittent fasting, an eating pattern that alternates periods of fasting and eating, may lower blood pressure and help some people lose weight.

But an analysis presented at the American Heart Association’s Scientific Sessions Monday in Chicago casts doubt on the notion that intermittent fasting is good for heart health. Instead, researchers at the Shanghai Jiao Tong University School of Medicine in China found that people who restricted their food intake to less than eight hours a day had a 91% higher risk of dying from cardiovascular disease over a median eight years than those who did not. I found it to be expensive. I ate it over 12 to 16 hours.

This is part of the first study to examine the link between time-restricted eating (a type of intermittent fasting) and the risk of death from cardiovascular disease.

The analysis, which has not yet been peer-reviewed or published in an academic journal, is based on data from the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey collected between 2003 and 2018. Researchers analyzed responses from nearly 20,000 adults.People who recorded what they ate for at least two days and who died from cardiovascular disease after a median follow-up The period is 8 years.

However, Victor Wenze Zhong, co-author of the analysis, said it was too early to make specific recommendations for intermittent fasting based solely on his research.

“Practicing intermittent fasting for short periods, such as three months, may be effective in reducing weight and improving cardiometabolic health,” Zhong said in an email. But he added that people “should be very careful” about intermittent fasting for long periods of time, such as several years.

There are many different types of intermittent fasting therapy. A common schedule is to limit his eating to 6 to 8 hours per day. This reduces your calorie intake, but some people eat the same amount in a shorter amount of time. Another popular schedule is the “5:2 diet,” where he eats 500 to 600 calories on two non-consecutive days of the week and eats normally the other five days of the week.

Zhong said it’s unclear why his study found an association between time-restricted eating and risk of death from cardiovascular disease. However, he expressed the following opinion. People who restricted their eating to less than eight hours a day had less lean muscle mass than those who ate for 12 to 16 hours a day. Low lean muscle mass has been shown to increase the risk of cardiovascular death.

Cardiovascular and nutritional experts not involved in the analysis offered several theories about what could explain the results.

Fasting can increase stress hormones like cortisol and adrenaline because your body doesn’t know when it’s going to eat next and goes into survival mode, says Dr. Benjamin Horn, a research professor at Intermountain Health in Salt Lake City. He said that there is a sex. This added stress can increase the short-term risk of heart disease, especially in vulnerable populations such as the elderly and people with chronic conditions, he said.

Horn’s study found that fasting twice a week for four weeks, followed by once a week for 22 weeks, increased the risk of death after one year, but decreased the risk of chronic disease over 10 years. It has been shown that it is possible.

“In the long term, you can reduce your risk factors for heart disease and risk factors like diabetes, but in the short term, your body is actually at risk while doing that. There’s a higher risk of problems happening,” he said.

Still, Horne said the analysis “doesn’t change my view that there are clear benefits to fasting, but it is a warning that we need to be aware of the clear and potentially significant negative effects.” added.

Intermittent fasting gained popularity around 10 years ago when the 5:2 diet was promoted as a weight loss strategy in the UK. In the years that followed, several celebrities espoused the benefits of his 8-hour eating window for weight loss, while some Silicon Valley tech workers believed that extreme fasting periods boosted productivity. I believed that. Some studies suggest that intermittent fasting may help prevent disease and extend lifespan.

However, much of the early research on intermittent fasting was in animals. Over the past seven years or so, various clinical trials have investigated its potential benefits for humans, including for heart health.

“The goal of intermittent fasting is to reduce calories and lose weight,” says Penny Chris Etherton, professor emeritus of nutritional sciences at Penn State University and a member of the American Heart Association’s nutrition committee. “How intermittent fasting is implemented explains many of the benefits and negative effects.”

Dr. Francisco López Jiménez, a cardiologist at the Mayo Clinic, said the timing of people’s meals can influence the visible effects.

“I have never met a single person or patient who practiced intermittent fasting by skipping dinner,” he said, noting that people skip breakfast, which is associated with an increased risk of heart disease and death. He pointed out that there are many.

New research has its limits. The study relied on people’s memories of what they ate over a 24-hour period, and did not take into account the nutritional value of the food they ate or the calories they burned during the meal period.

As a result, some experts judged the analysis too narrow.

“This is a retrospective study that looks at two days of data and draws some very big conclusions from a very limited snapshot of an individual’s lifestyle,” said Dr. Pam Taub, a cardiologist at the University of California, San Diego. It’s research.”

Taub said her patients see “incredible benefits” from fasting therapy.

“I want to keep it going,” she said. “For those who practice intermittent fasting, the individual results speak for themselves. Most people who practice intermittent fasting continue with it because they see weight loss. Lower blood pressure. We see improvement in LDL cholesterol.”

However, Professor Chris Etherton cautioned: “You may want to consider pausing intermittent fasting until more information is available or the research findings are better explained.” urged.