Intermittent fasting, an association discovered between the 16:8 scheme and the risk of cardiovascular disorders

The so-called intermittent fasting 16:8that is, which concentrates all meals in just eight hours of the day, could have long-term repercussions not as positive as you think. One says it preliminary study just presented during the Scientific Sessions dedicated to lifestyles and cardiometabolic health of theAmerican Heart Association, an important conference underway in Chicago. An analysis carried out on over 20 thousand US adults reported that “people who limited their food consumption to less than eight hours a day were more likely to die of cardiovascular disease”, as stated in the official note from the Aha (which however does not necessarily represent the association's position) compared to people who expanded this window to 12-16 hours a day.

“Limiting daily meal time to a short period, such as eight hours a day, has gained popularity in recent years as a way to lose weight and improve heart health,” explained the study's senior author, Victor Wenze ZhongPh.D., professor and chair of the department of epidemiology and biostatistics at Shanghai Jiao Tong University School of Medicine, China – however, the long-term health effects of time-of-day limited eating, including the risk of death from any cause or cardiovascular disease, they are unknown».

In the study, researchers investigated the potential long-term health impact of following an eight-hour time-restricted eating plan. They therefore examined information on the eating patterns of the annual participants National Health and Nutrition Examination Surveys 2003-2018 by comparing them with data on deaths in the United States from 2003 to December 2019 from the National Centers for Disease Control and Prevention.

• People who ate all meals for less than eight hours a day had a risk of death from cardiovascular disease higher than 91%;

• Increased risk of cardiovascular death was observed even in people living with heart disease or cancer;

• Among people with existing cardiovascular disease, a meal duration of no less than eight ma less than ten hours a day it was also associated with a 66% higher risk of death from heart disease or stroke;

• Eating for a limited period it did not reduce the overall risk of death from any cause;

• Meal duration greater than 16 hours per day was associated with a lower risk of cancer mortality among people with cancer.

“We were surprised to find that people on an eight-hour, time-restricted eating schedule were more likely to die from cardiovascular disease. While this type of diet has become popular due to its potential short-term benefits, our research clearly shows that, compared to a typical eating time frame of 12-16 hours per day, shorter meal times were not associated with longer life – continues Zhong – it is essential that patients, particularly those with existing heart disease or cancer, are aware of the association between an eight-hour eating window and an increased risk of cardiovascular death. The results of our study are encouraging a more cautious and personalized approach to dietary recommendationsensuring that they are in line with the individual's health status and with the latest scientific evidence.”

Obviously we're talking about association and not causationthis must be clarified and the scientists themselves do it: «Although the study identified an association between an eight-hour eating window and cardiovascular death, this does not mean that time-restricted eating caused cardiovascular death».

The investigation has indeed many strong limitations. For example, reliance on self-reported dietary information by subjects, which may be influenced by memory and may not accurately assess typical eating patterns. Additionally, factors that might play a role in overall health, outside of daily eating duration and cause of death, were not included. Future research should therefore examine i biological mechanisms that underlie associations between a time-restricted eating schedule and adverse cardiovascular outcomes, and whether these findings are similar for people living in other parts of the world, the authors noted. So as to bring that association closer or closer to some reason of causality.

Overall, however, the survey suggests that «Time-limited eating can have short-term benefits but long-term negative effects. When the study is presented in its entirety, it will be interesting and useful to know more details of the analysis – he explained Christopher D. GardnerPh.D., FAHA, professor of medicine at Stanford University in Stanford and involved in the American Heart Association – one of these details concerns the nutritional quality of the typical diets of the different subgroups of participants. Without this information it is not possible to determine whether nutrient density could be an alternative explanation for findings that currently focus on the eating window. Secondly, it should be emphasized that the categorization into different time-limited feeding windows was determined based on just two days of food intake».

It's not enough: «It will also be fundamental – adds the expert – to evaluate a comparison of demographic data and basic characteristics between the groups that were classified into the different time-limited eating windows. For example, was the group with the shortest time-restricted eating window unique from people who followed other eating patterns, in terms of weight, stress, traditional cardiometabolic risk factors, or other factors associated with adverse cardiovascular outcomes? This additional information will help to better understand the potential independent contribution of the time-limited dietary pattern reported here interesting and provocative abstract».

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