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Shifts in meal timing, particularly to a later breakfast, may reflect health changes in older adults that are linked to morbidity and mortality, an analysis of close to 3000 community-dwelling adults in the UK showed.

Older adults are vulnerable to “mistimed food intake” because of health or environmental factors, which means they’re eating at times that don’t align well with the body’s natural circadian rhythms, lead author Hassan Dashti, PhD, assistant professor, Harvard Medical School and a nutrition scientist and circadian biologist at Massachusetts General Hospital, told Medscape Medical News. 

“For example,” he said, “eating very late at night can create a mismatch between when the body expects food and when it actually receives it. This mismatch may disrupt metabolism, sleep, and other biological processes, which is why meal timing can matter for health.”

Although the study did not evaluate the impact of strategies such as intermittent fasting, “we did find that delaying meals, something that can resemble a form of ‘fasting,’ may not always be beneficial for older adults,” he noted. “For this population, maintaining regular and consistent meal times may be more supportive of better health and aging.” 

The study was published online in Communications Medicine.

Longer Survival With Early Eating

The researchers analyzed data from 2945 community-dwelling older adults from the University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age who were followed for a mean of 22 years. Participants’ mean age at recruitment was 64 years; 72% were women and 83.3% were unemployed. They underwent up to five self-reported repeated assessments of meal timing and health behaviors between 1983 and 2017.

In addition, during enrollment, participants completed the Pittsburgh Sleep Quality Index once, to compute scores reflecting sleep quality.

Furthermore, in a subset of participants, DNA was extracted from blood samples collected between 1999 and 2004. Genome-wide polygenic scores for eveningness (ie, later chronotype) and obesity (ie, higher BMI) — scores with known associations with meal timing — were calculated for each participant, and the Cornell Medical Index was administered four times to assess 19 symptoms of physical and psychological illness (ie, morbidity).

The 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, such as fatigue, oral health problems, depression, anxiety, and multimorbidity, were mainly associated with later breakfast. 

Genetic profiles related to an evening chronotype, but not obesity, were linked to later meals. Later breakfast timing was also associated with increased mortality. 

A latent class analysis of meal timing trajectories identified early and late eating groups, with 10-year survival rates of 86.7% in the late eating group compared to 89.5% in the early eating group.

The authors concluded that “meal timing, particularly later breakfast, shifts with age and may reflect broader health changes in older adults, with implications for morbidity and longevity.”

Consistent Meal Schedules Key

The authors acknowledged study limitations, including self-reported data and a lack of established variables for chrononutrition, making it difficult to compare results across studies and cohorts; inability to identify other meal timing variables such as snacks, meal frequency, and skipping behaviors; and lack of information on timing of consumption of specific nutrients, such as protein, which has been shown to associate with skeletal muscle mass in older adults when ingested before sleep.

Nevertheless, Dashti suggested, “Breakfast timing may reflect underlying changes in physiology, such as reduced morning appetite, fatigue, or health problems that make it harder to start the day, making it a particularly 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, “Next steps for this research include testing whether adjusting meal timing, such as encouraging earlier breakfasts or maintaining consistent meal schedules, can directly improve health and longevity in older adults.” 

“In the meantime, the main message is that maintaining regular, consistent meal schedules may support healthier aging, and that changes in appetite or unexpected weight loss should be monitored closely, as they may signal conditions such as anorexia of aging.”

A Potential Early Warning Sign

Monica Dinu, PhD, assistant professor at the University of Florence, and co-author of a recent study showing the benefits of aligning meals with chronotype in adults with overweight and obesity, commented on the study for Medscape Medical News. “The results are persuasive in showing that a shift toward later breakfasts in older adults tracks with greater morbidity and higher mortality risk. I see breakfast timing less as a cause and more as a simple, practical marker of underlying health changes.

“Later breakfasts probably reflect things like depression, fatigue, poor sleep, or oral health problems rather than directly causing illness,” said Dinu, who was not involved in the study. In addition to the noted limitations, “participants were mostly healthy, community-dwelling UK adults of European ancestry, so the results don’t necessarily apply to everyone. And while the associations were statistically strong, the effect sizes themselves were fairly modest.

“Breakfast tends to be the most sensitive to disruption,” she noted. “Issues like illness, low mood, poor sleep, pain, or oral problems often affect the first meal of the day the most. From a biological standpoint, the morning is when metabolism is primed to handle nutrients. A shift to later eating can reflect circadian phase delays, which themselves are linked to poorer health.” 

Future studies could include the development of more objective tools to track diet and meal timing; investigations of appetite hormones, circadian rhythms, and the microbiome to understand the mechanisms at play; and studies in more diverse populations and care settings, she said.

“For now, a simple question like ‘Has your breakfast time shifted later?’ might serve as an early warning sign of declining health,” she said. “Later breakfasts should prompt clinicians to screen for things like depression, sleep problems, oral health decline, or functional limitations.”

Like Dashti, she suggested, “Encouraging patients to eat earlier and more regularly, in line with their natural sleep-wake cycle, could be a small but meaningful way to support healthier aging.” 

The study was supported by the US National Institutes of Health. Dashti and Dinu declared no competing interests. 

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.