Do you sometimes have breakfast closer to lunchtime on weekends and eat dinner at a time when you would normally already be asleep? Scientists call this mismatch “social jetlag” of eating, or “food jetlag,” and it may be harmful to men’s heart health — with the effect observed only in men.
Early starts to the workday or school day often force people to shift their meal times on weekdays, creating a schedule that differs from their eating patterns on weekends and days off.
Shifts in eating schedules may disrupt the body’s biological rhythms and have consequences for cardiovascular health, according to a new French study, Euronews reports. Each additional hour of “food jetlag” was associated with a 14% higher risk of cardiovascular disease and a 21% higher risk of coronary heart disease in men.
“This study shows that maintaining regular meal timing plays an important role in cardiovascular disease prevention, alongside sleep and diet quality,” the authors write.
Published in the journal Communications Medicine, the study analyzed the timing of participants’ first and last meals on weekdays and weekends. More than 100,000 participants were followed over a 14-year period, from 2009 to 2023.
Participants were divided into groups according to their eating patterns: the first group ate earlier on weekends than on weekdays, the second followed approximately the same schedule, and the third ate later on weekends.
Both groups that shifted their meal times — either earlier or later than usual — had a higher risk of cardiovascular disease than those who maintained a regular schedule, regardless of overall diet quality.
Unexpectedly, this effect was observed only in men. In women, changes in meal timing did not have a significant impact.
Why?One possible explanation is that men generally have a higher absolute risk of cardiovascular disease. The authors also note that women are more likely than men to have a morning-oriented lifestyle. This difference, which is related to anatomical and hormonal factors, may affect how the body responds to shifts in meal timing.
The authors’ main hypothesis is that food jetlag increases the risk of cardiovascular events by disrupting circadian rhythms.
Circadian rhythms are the body’s internal clock, operating on a 24-hour cycle and regulating its functions. They are primarily synchronized by light, but meal timing can also act as a synchronizing signal for peripheral clocks, such as those in the liver and heart. When meals are aligned with these internal rhythms, this supports metabolic health, whereas a mismatch can disrupt the body’s internal balance.
The authors note that if these findings are confirmed in further large-scale studies, regular meal timing could become an important target for preventive measures aimed at reducing the risk of chronic diseases and easing the burden on healthcare systems.
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