the study They analyzed data on the dietary habits of 20,000 adults across the United States who were followed from 2003 to 2018. They found people adhering to an 8-hour eating plan. People who followed a more traditional eating pattern of eating over 12 to 16 hours each day had a 91 percent higher risk of dying from heart disease.

Scientists have found that this increased risk also applies to people who already have a chronic illness or cancer. People with pre-existing cardiovascular disease and following a time-restricted eating pattern had a 66 percent higher risk of dying from heart disease or stroke. On the other hand, cancer patients who followed a time-restricted diet were more likely to die from the disease than those who continued eating for at least 16 hours a day.

The study results suggest that people who practice long-term intermittent fasting “need to be very careful,” especially those who already have heart disease or cancer, said lead author Epidemiology.・Victor Wenze Zhong, head of the Department of Biostatistics, said: at Shanghai Jiao Tong University School of Medicine, China.

“Based on the current evidence, what “People seem to be more concerned about eating than focusing on when to eat,” he added.

Zhong said he and his colleagues conducted the new study because they wanted to know how eating a narrow range of meals every day affects “hard endpoints” such as heart disease and mortality. Stated. They were surprised by the discovery, he said.

“We expected that long-term implementation of eight-hour food restriction would lead to a reduced risk of cardiovascular disease and even all-cause mortality,” he said.

The data did not explain why time-restricted eating increases people’s health risks. However, researchers found that people who followed a 16:8 time-restricted eating pattern (eating during 8 hours and fasting for 16 hours) were less likely to eat during a longer period of the day. In comparison, they found that they had less lean muscle mass. This is consistent with a previous clinical study published in JAMA Internal Medicine. The clinical trial found that people assigned to follow a time-restricted diet for three months lost more muscle than a control group who were not assigned to intermittent fasting.

Maintaining muscle mass as you age is important. Protects against falls and injuries and promotes metabolic health. According to Zhong, research has shown that having less muscle mass has a higher mortality rate, including an increased risk of dying from heart disease.

He stressed that the findings are not conclusive. The study found a correlation between time-restricted eating and increased mortality, but could not show cause and effect. For example, people who limit their food intake to no more than eight hours a day may have had other habits or risk factors that could explain their increased likelihood of dying from heart disease. The scientists also noted that the study relied on self-reported dietary information. It is possible that participants did not always accurately report meal times.

Trending forms of diet and weight management

Intermittent fasting is widely touted by celebrities and health experts as leading to weight loss and various health benefits. Another form of intermittent fasting involves alternating fasting days with regular eating days. Some people do a 5:2 diet, where during the week he eats normally for 5 days, then fasts for 2 days.

However, time-restricted eating is generally considered to be the easiest form of intermittent fasting for people because it does not require a full day of fasting. Also, they usually do not have excessive dietary restrictions. Adherents often eat and drink whatever they want during the eight-hour eating period, with the only rule being that they don’t eat at any other time.

Some of the early studies on time-restricted eating found that it helped prevent the development of obesity and metabolic syndrome in mice. Small human clinical trials have since been conducted, some of which have shown that time-restricted eating can help people lose weight and improve blood pressure, blood sugar, and cholesterol levels. Ta. These studies were mainly short-term, usually lasting one to three months, and in some cases no effects were seen.

One of the most rigorous studies on time-restricted eating was published in the New England Journal of Medicine in 2022. In that study, obese patients who were assigned to follow a low-calorie diet and instructed to only eat between 8 a.m. and 4 p.m. each day had no restrictions on eating times during the day. They did not lose as much weight as people who consumed the same amount of calories through the diet. The two diets had similar effects on blood pressure, blood sugar, cholesterol, and other metabolic markers.

The findings suggest that the benefits of time-restricted eating likely result from reduced calorie intake.

Other questions about intermittent fasting

Christopher Gardner, director of nutrition research at the Stanford Prevention Research Center, said he encourages people to approach this new study with a “healthy skepticism.” He said that while the study results are interesting, he would like to see all the data, including potential demographic differences between the study participants.

“Did they all have the same level of disposable income and the same level of stress?” he says. “Or maybe people who eat less than eight hours a day work three jobs and are under such high stress that they don’t have time to eat?”

Gardner said studying intermittent fasting is important because there are so many variations of it and we need to closely observe people over long periods of time to determine its impact on longevity. said it can be difficult.

But so far, the evidence supporting intermittent fasting for weight loss and other benefits is mixed at best, with some studies showing short-term benefits and others showing no effect at all. he said. “I don’t think the data is very strong for intermittent fasting,” he added. “One of the challenges in nutrition, he says, is that just because something works very well for some people doesn’t mean it will work for everyone.”

He said his biggest complaint about intermittent fasting is that it doesn’t address diet quality. “There’s nothing written about making bad choices when eating,” he said. “He has eight hours to eat, so what if he’s eating Pop-Tarts or Cheetos and drinking coke during that time? I’m not a big long-term fan. That’s potentially problematic. I think.”

Have questions about healthy eating? Email EatingLab@washpost.com I may answer your question in a future column.