Study Links Later Breakfast Times to Higher 10-Year Mortality Risk

A government-funded, long-term study from researchers at Mass General Brigham, a Harvard-affiliated hospital system, found that people who delay breakfast tend to have worse health outcomes and a modestly higher risk of death over 10 years than those who eat earlier in the day.

The team followed nearly 3,000 middle-aged and older adults for almost 25 years, tracking reported meal timings and health measures. Investigators reported that participants generally shifted both breakfast and dinner to later times as they aged and that the interval between the two meals shortened. After accounting for measured factors, delaying the first meal of the day was associated with higher rates of depression, increased fatigue and poorer oral health, and late eaters were about 8% more likely to die within 10 years than those who ate earlier in the day.

The researchers observed an elevated risk of oral health problems among participants who tended to have dinner later in the evening, compared with those who ate earlier. In describing possible mechanisms, the study team said later mealtimes may interfere with the body's circadian rhythm — the internal clock that coordinates sleep, hormone production and body temperature — and with communication between organs such as the liver and the gut. Disruption of these rhythms, the authors suggested, could undermine sleep quality, which has been linked in other research to greater risk for chronic diseases.

The analysis was observational and therefore cannot prove cause and effect. The study relied on meal-time reporting and health assessments gathered over decades, which can be influenced by changing behaviors, recall errors and factors that were not measured. Investigators noted that as people age, modifications to daily routines, medication schedules, dental status and socioeconomic circumstances also affect when and how they eat, and such variables can confound associations between meal timing and later health outcomes.

The findings add to a body of research examining the relationship between circadian biology and metabolic and mental health. Prior studies have linked irregular or late eating schedules to sleep disturbance, impaired glucose regulation and measures of inflammation, but randomized trials testing whether deliberately shifting meal times alters long-term health outcomes are limited.

Public health experts said the results suggest that meal timing may be one modifiable behavior worth considering alongside diet quality, physical activity and sleep hygiene, particularly for older adults whose routines change over time. The study authors recommended further research, including trials and studies in more diverse populations, to determine whether changing mealtimes can improve sleep, oral health or mortality risk and to clarify the physiological pathways involved.

Until more definitive evidence is available, clinicians and patients may weigh meal timing as part of a broader approach to healthy aging, while recognizing that individual needs and circumstances — including medical conditions, work schedules and access to care — will affect the feasibility of altering eating patterns.