Shifts in meal timing, particularly later breakfasts, may indicate underlying health changes in older adults, potentially linked to morbidity and mortality, according to an analysis of nearly 3,000 community-dwelling adults in the UK.

Older adults can be especially vulnerable to “mistimed food intake,” where meals do not align with the body’s natural circadian rhythms, explained lead author Hassan Dashti, PhD, assistant professor at Harvard Medical School and nutrition scientist at Massachusetts General Hospital.

“For instance, eating very late at night can create a mismatch between when the body expects food and when it actually receives it,” Dashti told Medscape Medical News. “This can disrupt metabolism, sleep, and other biological processes, which is why meal timing matters for health.”

While the study did not assess interventions such as intermittent fasting, Dashti noted, “Delaying meals, which can resemble fasting, may not always benefit older adults. Maintaining regular and consistent meal times may better support health and healthy ageing.”

The study, published in Communications Medicine, analysed data from 2,945 participants in the University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age. The participants, with a mean age of 64 at recruitment, were followed for an average of 22 years. Assessments included self-reported meal timing, health behaviours, sleep quality, and, for a subset, DNA analysis to calculate polygenic scores for eveningness (later chronotype) and obesity.

Researchers found that older age was associated with later breakfast and dinner times, a later eating midpoint, and a shorter daily eating window. Physical and psychological illnesses — including fatigue, oral health problems, depression, anxiety, and multimorbidity — were most strongly associated with later breakfast. Genetic predisposition to an evening chronotype, but not obesity, was also linked to delayed meals.

A latent class analysis identified early and late eating groups. Ten-year survival rates were 86.7% in the late eating group versus 89.5% in the early eating group, highlighting the potential link between breakfast timing and longevity.

Consistent Meal Timing Supports Health

The authors acknowledged limitations, including reliance on self-reported data, lack of information on snacks, meal frequency, nutrient timing, and the relatively healthy, community-dwelling, predominantly European ancestry cohort.

Nevertheless, Dashti suggested, “Breakfast timing may reflect underlying physiological changes, such as reduced morning appetite, fatigue, or other health problems, making it a sensitive marker of overall health in older adults. Lunch and dinner are often shaped by social or cultural routines, which may explain why their timing showed weaker associations.”

He added that future research could explore whether encouraging earlier breakfasts or maintaining consistent meal schedules directly improves health and longevity. “In the meantime, maintaining regular meal schedules may support healthier ageing, and changes in appetite or unexpected weight loss should be monitored as potential warning signs,” he said.

An Early Warning Sign

Monica Dinu, PhD, assistant professor at the University of Florence, who has studied meal timing in adults with overweight and obesity, described breakfast timing as “a simple, practical marker of underlying health changes rather than a direct cause of illness.”

“Later breakfasts often reflect conditions such as depression, fatigue, poor sleep, or oral health problems,” Dinu said. “Morning meals are particularly sensitive to disruption. A shift to later eating may reflect circadian phase delays, which themselves are linked to poorer health.”

She recommended that clinicians consider asking older adults whether their breakfast time has shifted as an early warning sign. “Encouraging earlier, more regular meals aligned with natural sleep-wake cycles could be a simple but meaningful strategy to support healthier ageing,” Dinu added.