Research that analyzed data from more than 20,000 adults with an average age of 49 in the United States has revealed that people who restricted their food intake to less than eight hours a day according to a restricted eating plan of time were more likely to die from cardiovascular diseases compared to those who spread their meals over a period of 12 to 16 hours a day.
This preliminary finding has been presented at the American Heart Association’s Scientific Sessions on Epidemiology and Prevention/Lifestyle and Cardiometabolism 2024, which is being held in Chicago from March 18 to 21. The event focused on the latest research on population-based health and well-being, as well as its implications for lifestyle.
Time-restricted feeding is a form of intermittent fasting and involves limiting eating hours to a specific number of hours each day, which can vary between a 4- to 12-hour window in a 24-hour period. It has been observed that many people who adopt this diet follow a 16:8 eating schedule, consuming all their food in an eight-hour window and fasting for the remaining 16 hours each day. Previous research has shown that time-restricted feeding improves several measures of cardiometabolic health, such as blood pressure, blood glucose levels, and cholesterol.
“Restricting daily food intake to a short period, such as 8 hours a day, has gained popularity in recent years as a method to lose weight and improve cardiovascular health,” said the study’s lead author, Victor Wenze Zhong. , professor and head of the department of epidemiology and biostatistics at Shanghai Jiao Tong University School of Medicine, China. “However, the long-term effects of time-restricted feeding, including the risk of death from any cause or from cardiovascular disease, are unknown.”
A more cautious and personalized approach to dietary recommendations
Participants were followed for a median of 8 years and a maximum of 17 years. The study included data from participants in the annual National Health and Nutrition Surveys (NHANES) from 2003 to 2018 who were at least 20 years old at enrollment and had completed two 24-hour dietary recall questionnaires within the first year of enrollment. inscription. Approximately half of the participants identified as men and the other half as women.
Researchers examined the possible long-term impact of following an 8-hour time-restricted eating plan. They reviewed information on the dietary patterns of participants in annual NHANES from 2003 to 2018, compared with data on people who died in the US from 2003 to December 2019, obtained from the Centers’ National Death Index database. for Disease Control and Prevention.
The main findings of the analysis have been:
- People who consumed all their food in a period of less than 8 hours a day had a 91% greater risk of dying from cardiovascular diseases.
- The increased risk of cardiovascular death was also seen in people with heart disease or cancer.
- Among people with existing cardiovascular diseases, an eating duration of no less than 8 hours, but less than 10 hours a day was also associated with a 66% higher risk of death from heart disease or stroke.
- Time-restricted feeding did not reduce the overall risk of death from any cause.
- An eating duration of more than 16 hours per day was associated with a lower risk of cancer mortality among cancer patients.
“We were surprised to find that people who followed an 8-hour eating schedule were more likely to die from cardiovascular disease. Although this type of diet has been popular due to its potential short-term benefits, our research clearly shows that, compared to a typical feeding time range of 12 to 16 hours a day, a shorter duration of the intake was not associated with greater longevity,” Zhong explained.
“Although the study identified an association between an 8-hour feeding window and cardiovascular death, this does not mean that time-restricted feeding caused cardiovascular death.”
“It is crucial that patients, especially those with existing heart conditions or cancer, are aware of the association between an 8-hour feeding window and an increased risk of cardiovascular death. The findings of our study promote a more cautious and personalized approach to dietary recommendations, ensuring that they are aligned with the health status of the individual and the most recent scientific evidence,” he continued. “Although the study identified an association between an 8-hour feeding window and cardiovascular death, this does not mean that time-restricted feeding caused cardiovascular death.”
For Tom Sanders, Emeritus Professor of Nutrition and Dietetics at King’s College London (United Kingdom), he points out a possible explanation in statements to the Social Media Center (SMC) of the United Kingdom “With respect to cardiovascular risk factors, we know from evidence existing knowledge that it is probably better to distribute food intake throughout the day (small but frequent) rather than consuming large meals in a shorter period. This is because large increases in fat and blood glucose occur after large meals. These postprandial increases [después de comer] in blood fats and glucose can alter endothelial function and increase the level of blood clotting factors, particularly factor VII. Prolonged fasting can contribute to increasing blood cholesterol because it promotes the release of fatty acids from adipose tissue that stimulate the synthesis of very low-density lipoproteins in the liver, which give rise to low-density lipoproteins in the blood.
Limitations of the study included its reliance on self-reported dietary information, which may be influenced by participants’ memory or recall, and which may not accurately assess typical eating patterns. Other factors that may affect health, besides daily duration of intake and cause of death, were not included in the analysis.
Duane Mellor, registered dietitian and senior lecturer at Aston School of Medicine, Aston University, UK, who was not involved in the study, also highlighted that the research presented at the conference has many limitations and could raise alarm. unjustified. In statements also collected by SMC he points out that “although a model was used to assess risk, it is not clear if it included the healthy diet pattern, or even what people ate. Because data are limited, it is not clear from the available data whether variables such as smoking, physical activity, and alcohol consumption were considered.”
“It is impossible to say whether restricting the time a person eats is related to the risk of health outcomes, as this summary suggests, because it is not clear because the data are so limited and based on two days of eating.” memory of the diet, why they might have been restricting the time they ate. “Some people might be doing this for health reasons, while others because of stressful work environments or poverty, which are risk factors for cardiovascular death.”
“Perhaps what you eat and your lifestyle in general is more important than whether you ate all your food in less than 8 hours in two days in the last decade,” concludes this expert.
