March 19, 2024
A new analysis challenges the notion that restricting eating to a limited window of time is good for heart health.
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Research presented Monday at the American Heart Association’s scientific sessions in Chicago challenged the notion that intermittent fasting, a diet pattern that involves alternating between periods of fasting and eating ,is good for heart health.
In some of the first research investigating the association between time-restricted eating, researchers from China found that people who restricted food consumption to less than eight hours per day had a 91% higher risk of dying from cardiovascular disease over a median period of eight years, relative to people who ate across 12 to 16 hours.
The analysis is not yet peer-reviewed or published in an academic journal.
The study is based on data from the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey collected between 2003 and 2018.
The researchers analyzed responses from around 20,000 adults who recorded what they ate for at least two days, then looked at who had died from cardiovascular disease after a median follow-up period of eight years.
Researchers warned it was too early to make recommendations about intermittent fasting based on his research alone saying that practicing intermittent fasting for a short period such as 3 months may likely lead to benefits on reducing weight and improving cardiometabolic health, but people “should be extremely cautious” about intermittent fasting for longer periods of time, such as years.
Intermittent fasting regimens vary widely. A common schedule is to restrict eating to a period of six to eight hours per day, which can lead people to consume fewer calories, though some eat the same amount in a shorter time. Another popular schedule is the “5:2 diet,” which involves eating 500 to 600 calories on two nonconsecutive days of the week but eating normally for the other five.
Researchers said it’s not clear why an association was found between time-restricted eating and a risk of death from cardiovascular disease. But they did offer an observation: People who limited their eating to fewer than eight hours per day had less lean muscle mass than those who ate for 12 to 16 hours. Low lean muscle mass has been linked to a higher risk of cardiovascular death.
Experts who were not involved in the analysis offered several theories about what might explain the results including that fasting can increase stress hormones such as cortisol and adrenaline, since the body doesn’t know when to expect food next and goes into survival mode. That added stress may raise the short-term risk of heart problems among vulnerable groups, he said, particularly elderly people or those with chronic health conditions.
Other experts stated that, In the long term, the diet reduces those risk factors for heart disease and reduces the risk factors for diabetes — but in the short term the body is in a state where it’s at a higher risk of having problems.
Some studies have also suggested that intermittent fasting might help extend people’s lifespan by warding off disease saying the purpose of intermittent fasting is to cut calories, lose weight, but it is how the diet is implemented that’s going to explain a lot of the benefits or adverse effects.
Dr. Francisco Lopez-Jimenez, a cardiologist at Mayo Clinic, said the timing of when people eat may influence the effects they see.
“I haven’t met a single person or patient that has been practicing intermittent fasting by skipping dinner,” he said, noting that people more often skip breakfast, a schedule associated with an increased risk of heart disease and death.