Jetlag Eating Tied to Higher Heart Disease Risk

Work often requires people to adjust their eating patterns during the week, resulting in differences in eating schedules between weekdays and weekends or days off—when meal timing tends to be more closely aligned with their internal biological clocks. This shift, known as eating jetlag, may disrupt the body's biological rhythm. Previous studies have already shown that disruptions to the biological clock linked to night work or late mealtimes can lead to cardiovascular complications.

The research team chose to assess the link between eating jetlag and the risk of cardiovascular disease within the NutriNet-Santé cohort. They analysed data from 104,806 adult NutriNet-Santé participants between 2009 and 2023. The severity of eating jetlag was calculated based on the timing of participants' first and last meals of the day on weekdays and weekends. The association between eating jetlag and the risk of cardiovascular disease was assessed using appropriate statistical models, which also took into account other factors such as age, marital status and the number of children living in the household, socio-occupational factors, smoking, alcohol consumption, physical activity, diet, sleep, etc. By comparing meal timing on weekdays and weekends, the researchers classified eating jetlag according to the magnitude of the difference into three categories:

• 'Advance', where mealtimes are earlier at the weekend than on weekdays, with an average of 2 hours' advance in the eating window;
• 'Regular', where the eating windows are similar;
• 'Delay', where mealtimes are later at the weekend than on weekdays, with an average delay of 1 hour 40 minutes in the eating window.

Eating jetlag associated with a higher risk of cardiovascular disease in men

For men, the results suggest that each additional hour of eating jetlag—be it earlier or later—is associated with an average 14% increased risk of cardiovascular disease and an average 21% increased risk of coronary heart disease. Both the 'Advance' and 'Delay' groups showed a higher risk compared with the 'Regular' group. The researchers did not find any significant difference among women. Several hypotheses may account for this finding. The first relates to sexual dimorphism, that is, differences in physiological functioning between the two biological sexes. The second relates to differences in lifestyle and socio-occupational circumstances between women and men in society, which could lead to different circadian rhythms. Finally, the absolute risk of cardiovascular disease is higher in men.

This initial study suggests that changes in mealtimes between weekdays and weekends may play a role in the development of cardiovascular disease, regardless of sleep and diet, particularly in men. Further studies are needed to build on this initial observational study and establish the causality of these links.

A few years ago, we suggested that eating late was associated with an increased risk of cardiovascular disease. This new study suggests that, beyond simply eating late, maintaining consistent meal times between weekdays and weekends may be just as important. These associations appear to be independent of how long people sleep, suggesting that regular meal times could, in themselves, help resynchronise our biological rhythm. We are continuing our research to better understand this phenomenon."

Bernard Srour, Research Director at INRAE