Most adults shift their sleep schedules on weekends — but a growing body of evidence suggests the same disruption applies to when they eat, with potentially serious consequences for the heart. This large-scale prospective study from France puts numbers to that risk, and the findings challenge the assumption that diet quality alone determines cardiovascular outcomes.
Drawing on over 104,000 participants from the NutriNet-Santé cohort tracked across a median of 8.1 years, researchers quantified "eating jetlag" — the absolute difference in the timing of first and last caloric intake between weekdays and weekends. Using multi-adjusted Cox proportional hazard models, they found that among male participants, greater eating jetlag was associated with a 14% higher overall cardiovascular disease risk (HR = 1.14, 95% CI 1.05–1.23) and a 21% elevated coronary heart disease risk (HR = 1.21, CI 1.11–1.33). Notably, both advancing meal timing on weekends (eating earlier) and delaying it (eating later) relative to weekdays were associated with elevated coronary risk — 68% and 36% higher, respectively — compared to those who maintained consistent schedules. The sex specificity of the findings — associations were not statistically significant in women — adds an intriguing layer requiring further investigation.
This research extends the circadian nutrition hypothesis, which posits that misalignment between internal biological clocks and actual eating behavior independently disrupts metabolic and cardiovascular regulation, beyond the well-studied effects of sleep timing. The study's scale and duration are genuine strengths; however, self-reported dietary records and cardiovascular outcomes introduce measurement limitations, and the predominantly female, higher-education cohort limits generalizability. Crucially, this is an observational association — causality cannot be established. The sex-specific effect is provocative but unexplained; hormonal factors and differing circadian sensitivity are plausible but speculative. Overall, this is a confirmatory and incrementally important contribution to chrono-nutrition, reinforcing that when people eat may matter as much as what they eat.
