Adults over 40 who reported eating their first meal after noon had a 29% higher risk of death from any cause than those eating between 7 and 8 a.m., though researchers caution that the observational findings do not prove late breakfasts cause earlier death.
By yourNEWS Media Newsroom
The time of day people eat their first meal may be associated with longevity, according to research involving more than 31,000 adults that found progressively higher mortality rates among participants who delayed breakfast later into the day.
Adults over 40 who ate their first meal after noon were associated with a 29% greater risk of death from any cause compared with participants who ate between 7 and 8 a.m., according to the study, published in the European Journal of Clinical Nutrition.
The association was even stronger for cardiovascular mortality. Participants whose first meal occurred after noon had a 46% higher risk of dying from a cardiovascular event, including heart attack or stroke, according to the findings reported by the New York Post.
Researchers also estimated that among adults 50 and older, later eating was associated with an average life expectancy nearly 2.5 years shorter.
The findings do not demonstrate that eating breakfast late directly causes premature death, however, and the researchers emphasized that meal timing could instead be an indicator of other health or lifestyle factors.
“Later eating should be interpreted as a potential risk marker, and possibly a modifiable behavior, rather than definitive evidence of a direct causal effect,” senior author Zhilei Shan told ScienceAlert.
The research drew on information from the National Health and Nutrition Examination Survey, according to registered dietitian nutritionist Molly Knudsen, M.S., RDN.
Participants, all 40 or older, recorded what they ate and when they ate it during a single 24-hour period. Researchers defined the interval between each participant’s first and final meals as that person’s eating window and then examined mortality outcomes in relation to the reported timing of the first meal.
People eating between 7 and 8 a.m. served as the comparison group.
The associations became progressively larger as breakfast moved later.
Participants whose first meal occurred between 8 and 10 a.m. had a 10% higher risk of death from any cause compared with the 7-to-8 a.m. group.
For those eating between 10 a.m. and noon, the associated increase reached 19%.
Among participants waiting until after noon, the difference climbed to 29%.
The pattern adds to growing scientific interest in chrononutrition — the study of how the timing of food intake interacts with the body’s internal biological clock.
Human physiology operates on circadian rhythms that influence numerous functions over approximately 24-hour cycles. Digestion, blood pressure, hormone secretion and metabolism are among the processes that fluctuate throughout the day, and most genes exhibit some degree of daily variation in their activity.
That means identical foods or quantities of calories may not necessarily produce identical metabolic responses when consumed at very different times.
Research examining late eating has found associations with impaired glucose regulation and reduced insulin sensitivity, suggesting that eating at times poorly aligned with circadian biology may influence how efficiently the body handles nutrients.
Carbohydrate timing and quantity can also affect blood-glucose responses, adding another potential mechanism through which the distribution of meals across the day could influence metabolic health.
Previous studies examining caloric distribution have similarly compared eating a larger proportion of daily calories earlier in the day with consuming heavier meals later. Some research has found differences in weight-loss outcomes even when total calorie intake is held constant.
Those findings have contributed to the theory that when a person eats could matter alongside what and how much the person consumes.
The new study does not establish that mechanism, however.
One significant limitation is that researchers assessed participants’ food timing using only a single 24-hour dietary record. One day of eating may not accurately represent someone’s typical breakfast schedule or long-term dietary habits.
Other potentially important factors were also not fully captured, including sleep schedules and the timing of physical activity.
A person routinely eating a first meal at noon, for example, could have a substantially different sleeping schedule from someone beginning breakfast at 7 a.m. Shift work, health status, medication use, appetite, socioeconomic circumstances and existing illness could also influence when someone eats.
Such factors make it difficult for an observational study to determine whether breakfast timing itself is responsible for differences in mortality.
Later eating could alternatively function as a marker for other behaviors or health conditions associated with increased risk.
The researchers therefore stopped short of recommending a specific breakfast time as a proven method of extending life.
Their findings instead add to evidence suggesting that the body’s response to food cannot always be separated from the biological timing of its consumption.
Regularity may be another consideration.
Nutrition experts generally recommend structuring meals in a way that supports stable energy and blood-glucose levels, with balanced combinations of protein, dietary fat and fiber rather than relying solely on rapidly digested foods.
Spacing meals roughly four to six hours apart may help some people maintain more consistent energy and metabolic responses throughout the day.
That advice does not mean everyone needs to eat at precisely the same times. Individual schedules, medical conditions, medications, exercise patterns and appetite can all influence an appropriate meal routine.
The study’s most notable finding is the dose-like pattern observed across breakfast times: mortality associations became progressively greater as the first meal moved from early morning toward midday and beyond.
Compared with breakfast between 7 and 8 a.m., the associated increase in all-cause mortality was 10% for an 8-to-10 a.m. first meal, 19% between 10 a.m. and noon and 29% after noon.
The cardiovascular association among the latest eaters was larger still, reaching 46%.
Those figures represent relative differences in risk between the groups rather than an individual’s absolute probability of dying during a particular period.
Researchers say additional studies will be necessary to determine whether moving breakfast earlier actually changes long-term health outcomes or whether meal timing primarily identifies people with other underlying risk factors.
For now, the findings strengthen the case for studying not only the nutritional quality and quantity of food but also its timing — while stopping short of establishing late breakfast as a direct cause of shortened life.
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