A late Saturday breakfast may create a form of metabolic jet lag even without travel.
PARIS, FRANCE
Frequently changing meal times between working days and weekends may be associated with a greater risk of cardiovascular disease among men, according to a large French study. Researchers analyzed information from 104,806 adults participating in the NutriNet-Santé cohort and examined what they call “eating jet lag”: the difference between the hours at which people eat during the week and on their days off.
For every additional hour of variation in meal timing, men showed a 14% higher relative risk of developing cardiovascular disease and a 21% higher risk of coronary heart disease. The association remained after researchers adjusted for diet quality, sleep duration, smoking, age and socioeconomic factors. No statistically significant relationship was detected among women.
Meal timing helps regulate the body’s circadian system. Light primarily synchronizes the central biological clock, while eating influences peripheral clocks in organs such as the liver and pancreas. Moving breakfast from early morning during the week to midday on weekends may disrupt metabolic processes connected to insulin secretion, blood pressure and the regulation of hunger.
The findings do not demonstrate that occasional late breakfasts directly cause heart disease. The research was observational, meaning that people with irregular eating schedules may differ in other ways that cannot be completely measured. The absence of a significant result among women also does not establish that they are protected; differences in biology, work schedules, baseline cardiovascular risk or statistical power may help explain the contrast.
The study’s implications may be particularly relevant for night-shift and rotating-shift employees, whose sleep and eating schedules are frequently disrupted by working conditions. Researchers suggest that meal-time regularity should be considered alongside sleep when evaluating occupational health, although additional studies are needed before specific clinical recommendations can be established.
Maintaining reasonably consistent meal times may support cardiovascular health, but it should complement rather than replace established measures such as nutritious food, physical activity, adequate sleep and medical care. The evidence favors regularity, not an inflexible timetable.
Health is shaped not only by what we consume, but by the rhythms we ask the body to follow.