Weekend ‘Eating Jetlag’ Tied to Higher Heart Disease Risk in Men

Sleeping in on a Saturday and pushing breakfast back a few hours can feel like a small, well-earned reward after a long week. A large new study out of France suggests that regularly shifting mealtimes between weekdays and weekends might carry a real cost, at least for men’s hearts.

Researchers followed more than 104,000 adults for over eight years and found that men whose eating schedules shifted noticeably between weekdays and weekends had a higher risk of heart disease, including a form of it caused by clogged arteries called coronary heart disease. The bigger the gap between a man’s weekday and weekend eating times, the higher his risk tended to climb. For coronary heart disease specifically, that held true whether the weekend shift ran earlier or later. Findings appear in the journal Communications Medicine.

Scientists are calling this pattern “eating jetlag,” a play on the term “social jetlag,” which describes the mismatch between sleep schedules on workdays and days off. Instead of tracking sleep, this study tracked the timing of people’s first and last meals each day and looked at what happens when that timing swings depending on the day of the week. The link only showed up in men. Women in the study saw no such connection, which raises real questions about why male and female bodies might respond so differently to inconsistent eating times.

How Scientists Tracked the Eating Jetlag Data

Data for this analysis came from a long-running French health project called NutriNet-Santé, which has collected health and lifestyle information from volunteers since 2009. Scientists drew on records from 104,806 adults, about 79% of them women, with an average age of 43.

To map out each person’s eating schedule, participants filled out food diaries several times, logging everything they ate and drank and exactly when. Each person completed close to six of these recorded days on average. From that, researchers calculated the midpoint of each person’s eating window, the halfway point in time between their first bite and their last, separately for workdays and non-working days.

Comparing those two midpoints let researchers measure how far someone’s eating schedule drifted between the two. People whose weekend eating midpoint landed more than an hour earlier than their weekday midpoint were labeled “Advance.” Those whose midpoint landed more than an hour later were “Delay.” Anyone within an hour in either direction was considered “Maintenance.”

Most people, about 71%, fell into the Maintenance group, meaning their eating patterns barely changed across the week. This group tended to be older, married, retired, and more likely to have young kids at home. Only about 5% landed in the Advance group, which skewed toward men with less formal education and higher unemployment rates. The remaining 24%, the Delay group, tended to be younger, single, and more likely to be students or working full time.

Researchers then tracked who developed heart disease over time, checking self-reported health updates against medical records and national health databases. Over a median follow-up of just over eight years, they recorded 2,368 new cases of cardiovascular disease, a category that includes 1,270 cases of coronary heart disease and 1,098 strokes or related events.

The Heart Disease Risk Numbers Behind Eating Jetlag

For every extra hour of mismatch between weekday and weekend eating, men faced roughly a 14% higher risk of cardiovascular disease overall and a 21% higher risk of coronary heart disease specifically. Men in the Advance group, who ate much earlier on weekends, had a 44% higher risk of cardiovascular disease and a 68% higher risk of coronary heart disease compared with men whose schedules stayed steady. Men in the Delay group, who ate later on weekends, had a 36% higher risk of coronary heart disease as well.

Stroke risk specifically showed no clear connection to eating jetlag, and women showed no meaningful link at all, no matter which direction their eating schedule shifted.

These patterns held up even after researchers adjusted for how much sleep people got, what time they went to bed, and how closely their sleep schedules matched the more familiar social jetlag pattern. The link also survived after accounting for overall diet quality, so it wasn’t simply that men with irregular eating schedules were eating worse food on weekends. Risk did level off once the mismatch grew beyond about an hour and a half, suggesting there’s a point past which more disruption doesn’t add much more danger.

Why Eating Jetlag Hits Men Harder Than Women

Study authors floated a few possible reasons why this pattern turned up in men but not women. Men generally have higher rates of heart disease, which could make it statistically easier to spot a link in that group. There may also be real biological differences in how men’s and women’s bodies react to shifts in meal timing. The researchers pointed to earlier lab work in mice, where a restricted eating schedule produced weight benefits only in male mice, not females, raising the possibility that biological sex shapes how eating rhythms interact with metabolism. Hormonal differences and variations in the genes that control the body’s internal clock might also factor in, though exactly how remains unclear.

Everyday life might play a part too. Men and women often keep different work schedules, carry different caregiving loads, and follow different daily routines, all of which could shape how much their eating patterns swing between weekdays and weekends, and how their bodies handle that swing.

The Study’s Limits and What It Means Going Forward

Researchers didn’t have direct information on people’s actual work schedules, so they assumed Monday through Friday counted as workdays, and Saturday and Sunday counted as rest days for everyone. That assumption probably doesn’t hold for shift workers or people with nontraditional jobs, though the study population skewed toward more educated people who likely keep standard office hours.

This is an observational study, meaning it can show a relationship between eating patterns and heart disease risk, but it can’t prove that irregular eating schedules directly cause heart problems. The volunteer pool also isn’t a perfect stand-in for the general population. It included more women, more health-conscious participants, and lower overall rates of heart disease than France as a whole. Researchers also left out anyone believed to be under-reporting their food intake, a standard step in nutrition research, but one that shrinks and reshapes the sample somewhat.

Eating jetlag, as defined here, only captures one narrow slice of meal-timing habits. The researchers suggest future work looking at day-to-day changes across the whole week, not just weekday-versus-weekend patterns, could fill in more of the picture.

None of this means a lazy weekend breakfast is dangerous on its own. What the study points to is something more specific: a habitual, repeated mismatch between weekday and weekend eating schedules, week after week, year after year, showing up alongside a real jump in heart disease risk in men. The researchers say their findings add to evidence that meal timing may matter alongside factors like sleep and diet quality for heart health. If future research backs this up, keeping a steadier eating schedule across the week, rather than letting it swing once the weekend hits, could be a simple, low-cost habit worth adopting.

Disclaimer: This article summarizes findings from a single observational study. Observational research can identify associations but cannot prove that eating jetlag directly causes heart disease. Results may not apply to everyone, as the study population was mostly women and more health-conscious and educated than the general population. This content is for informational purposes only and is not medical advice. Anyone with questions about their heart health or eating habits should consult a qualified healthcare provider.

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