A study of more than 20,000 adults found that those who followed an eight-hour time-restricted eating plan, a type of intermittent fasting, died fromThe risk of cardiovascular disease was 91% higher. People with heart disease or cancer also have an increased risk of cardiovascular death. Limiting eating to eight hours per day was not associated with longevity compared to a standard eating schedule of 12-16 hours per day.

An analysis of more than 20,000 U.S. adults found that those who restricted their eating time to less than eight hours a day were more likely to die from cardiovascular disease compared with those who ate 12-16 hours a day, according to preliminary research presented at the American Heart Association's Epidemiology and Prevention│2024 Lifestyle and Cardiometabolic Sciences Conference in Chicago from March 18-21. The conference provides the latest scientific information on population health and wellness and the implications for lifestyle.

Learn about time-restricted eating

Time-restricted eating is a type of intermittent fasting, which means limiting eating to a specific number of hours each day, ranging from 4 to 12 hours in a 24-hour period. Researchers note that many time-restricted eaters follow a 16:8 eating schedule, in which they eat all their food within eight hours of each day and fast for the remaining 16 hours. Previous research has found that time-restricted eating improves multiple measures of cardiometabolic health, such as blood pressure, blood sugar, and cholesterol levels.

Research findings and implications

"Limiting daily eating to a short period of time, such as eight hours a day, has become increasingly popular in recent years as a way to lose weight and improve heart health," said the study's senior author Dr. Victor Wenze Zhong, professor and chair of the Department of Epidemiology and Biostatistics at Shanghai Jiao Tong University School of Medicine in China. "However, the long-term health effects of time-restricted eating, including the risk of death from any cause or cardiovascular disease, are unknown."

Study details and limitations

In this study, researchers investigated the potential long-term health effects of following an eight-hour time-restricted eating plan. They examined information on dietary patterns among participants in the annual National Health and Nutrition Examination Survey (NHANES) from 2003 to 2018 and compared it with data on U.S. deaths from 2003 to December 2019 in the Centers for Disease Control and Prevention's National Death Index Database.

Analysis found:

  • People who eat less than 8 hours a day have a 91% higher risk of death from cardiovascular disease.

  • People with heart disease or cancer also have an increased risk of cardiovascular death.

  • Among people with cardiovascular disease, those who eat for at least eight hours but less than 10 hours a day have a 66% higher risk of dying from heart disease or stroke.

  • Time-restricted eating did not reduce the overall risk of death from any cause.

  • Eating for more than 16 hours a day is associated with a lower risk of cancer death in cancer patients.

    • "We were surprised to find that people who followed an eight-hour time-restricted eating plan were more likely to die from cardiovascular disease. Although this type of eating is popular for its potential short-term benefits, our study clearly shows that shorter eating periods are not associated with longer lifespan compared with the typical eating window of 12-16 hours per day," Zhong said. "It is critical for patients, especially those with heart disease or cancer, to understand the association between the eight-hour eating window and an increased risk of cardiovascular death. Our findings encourage a more cautious and personalized approach to dietary recommendations, ensuring they are consistent with an individual's health status and the latest scientific evidence. While this study found an association between the eight-hour eating window and cardiovascular death, it does not mean that time-restricted eating causes cardiovascular death."

    Research details and background:

  • The study subjects included about 20,000 U.S. adults, with an average age of 49.

  • Study participants were followed for a median of 8 years, with a maximum of 17 years.

  • The study included data from NHANES participants who were at least 20 years old between 2003 and 2018 and who completed two 24-hour dietary recall questionnaires within the first year of enrollment.

  • About half of the participants self-identified as male and half self-identified as female. 73.3% of participants self-identified as non-Hispanic white adults, 11% self-identified as Hispanic adults, 8% self-identified as non-Hispanic black adults, and 6.9% of adults self-identified as other races, including mixed-race adults and other non-Hispanic adults.

    • Limitations of the study include its reliance on self-reported dietary information, which may be affected by participants' memory or recall and may not accurately assess typical eating patterns. In addition to daily eating time and cause of death, other factors that may affect health were not included in the analysis.

    The authors note that future studies may examine the biological mechanisms underlying the association between restricted eating times and adverse cardiovascular outcomes, and whether these findings are similar to people living in other parts of the world.

    Expert opinions and future research directions

    "Overall, this study suggests that time-restricted eating may have short-term benefits but long-term adverse effects," said Dr. Christopher Gardner, the Reinberg-Farquhar Professor of Medicine at Stanford University in Stanford, California, and chair of the writing committee for the American Heart Association's 2023 scientific statement, "Popular Dietary Patterns." "It will be very interesting and helpful to know more details of the analysis when this study is fully presented: consistent with the American Heart Association's 2021 Dietary Guidelines."

    "One of these details concerns the nutritional quality of the typical diets of the different subsets of participants. Without this information, it is not possible to determine whether nutrient density could serve as an alternative explanation for the results of the current study, which focused on eating time windows. Secondly, it is important to emphasize that the classification of different time-restricted eating windows was based on dietary intake over two days."

    "It will also be critical that we see comparisons of the demographic and baseline characteristics of groups divided into different time-restricted eating windows - for example, are the group with the shortest time-restricted eating windows unique in terms of body weight, stress, traditional cardiometabolic risk factors, or other factors associated with adverse cardiovascular outcomes compared with people who follow other eating schedules? This additional information will help to better understand the potential independent contributions of short-time restricted eating patterns reported in this interesting and illuminating abstract."

    Compiled from:ScitechDaily