For many Europeans, the weekend brings a welcome break from the early alarms and rigid schedules of the working week. But a new study suggests that letting meal times drift on days off could have a hidden cost, particularly for men's cardiovascular health.
Researchers in France have coined the term “eating jet lag” to describe the discrepancy between when people eat on workdays and when they eat on weekends. Their findings, published in Communications Medicine, indicate that this pattern may disrupt the body's internal clocks and increase the risk of heart disease.
What the study found
The research followed more than 100,000 participants over a 14-year period, from 2009 to 2023, tracking the timing of their first and last meals on both working days and weekends. The team divided participants into three groups: those who ate earlier on weekends, those who kept similar schedules, and those who ate later.
Both the “earlier” and “later” groups showed a higher risk of cardiovascular problems compared to those with consistent meal times, regardless of overall diet quality. Specifically, each additional hour of eating jet lag was linked to a 14% increase in cardiovascular disease risk and a 21% increase in coronary heart disease risk.
Strikingly, this effect was observed only in men. Women appeared unaffected by changes in meal timing, a difference the authors attribute to variations in anatomy and hormones, as well as a tendency for women to prefer morning routines more than men.
“This study suggests the importance of regular meal-timing patterns, beyond sleep and diet quality, in cardiovascular disease prevention,” the authors wrote.
Why meal timing matters
The leading theory behind the findings is that eating jet lag disrupts circadian rhythms—the body's internal 24-hour clocks that regulate everything from sleep to metabolism. While light is the primary cue for these rhythms, eating patterns also help synchronise peripheral clocks in organs like the liver and heart.
When meal times shift significantly between weekdays and weekends, these peripheral clocks can fall out of sync, potentially leading to metabolic imbalances and increased cardiovascular strain. The study adds to a growing body of evidence linking irregular eating patterns to health outcomes.
Previous research has already shown that social jet lag in teenagers is linked to higher anxiety, and this new work suggests that similar disruptions in adults may have physical consequences.
For those with demanding work schedules, such as the long commutes seen in Belgium, where daily travel averages 61 minutes, maintaining consistent meal times can be challenging. Yet the study's authors emphasise that regular eating patterns could be a simple, low-cost addition to cardiovascular prevention strategies.
While the study is observational and cannot prove causation, its large sample size and long follow-up period lend weight to its conclusions. The researchers controlled for factors like sleep duration, diet quality, and physical activity, though they acknowledge that residual confounding is possible.
For now, the message for men in particular is clear: if you tend to push breakfast to noon on Saturdays and eat dinner late into the evening, your heart might be paying the price. Aligning weekend meals with your weekday routine could be a small change with significant benefits.
