A study by a team of scientists from Karolinska Institutet in Sweden has suggested that older people who typically had longer intervals between meals accumulated chronic diseases more rapidly over time than those with shorter intervals, particularly those over 78.
Their research was published in the Journal of Internal Medicine.
Interest in fasting has increased in recent years, but relatively little is known about how meal timing affects health in older adults. For this study, the researchers investigated whether the duration of the longest daily interval between meals was associated with the accumulation of chronic diseases over time.
They used data from the Swedish National Study on Ageing and Care in Kungsholmen (SNAC-K), which includes 2 981 people in Stockholm aged 60 or older at the start of the study. Participants were followed for up to 15 years.
The duration of intervals between meals was estimated from participants’ self-reported information about when they typically ate during a 24-hour period.
Seen across disease types
Longer intervals between meals were associated with faster accumulation of chronic diseases over time. In particular, people whose longest interval between meals during a typical day was 14 to 24 hours accumulated chronic diseases more rapidly than those whose longest interval was six to 11.5 hours.
The association was observed for the total number of chronic diseases, as well as for cardiovascular and neuropsychiatric diseases, but not for musculoskeletal diseases.
Differences
“Much of the research on fasting has been conducted in younger or middle-aged populations. Our findings suggest that the associations may be different in older adults, particularly among the oldest age groups,” said Adrián Carballo Casla, last author of the study and postdoctoral researcher at the Ageing Research Centre, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet.
The researchers added that the study cannot determine cause and effect. Although longer intervals between meals were linked to faster disease accumulation, the study cannot establish whether the fasting pattern independently contributed to this outcome.
Study details
Habitual fasting duration and accelerated multimorbidity in older adults
Luis Kalmbach, David Abbad-Gomez, Giorgi Beridze, Fernando Rodríguez-Artalejo, Davide Liborio Vetrano, Amaia Calderón-Larrañaga, Adrián Carballo-Casla.
Published in Journal of Internal Medicine on 20 August 2026
Abstract
Background
Prolonged fasting has been linked to metabolic benefits in younger adults, but its effects on chronic diseases in older populations remain unclear.
Objective
To examine the association between habitual fasting duration and 15-year chronic disease accumulation in older adults, overall, within organ systems, and between age groups.
Methods
Data were drawn from the Swedish National study on Ageing and Care in Kungsholmen, a longitudinal population-based cohort of 2981 predominantly community-dwelling adults aged ≥60 years. Habitual fasting duration was the longest interval between two typical eating occasions within a 24-h window. Multimorbidity was the total number of chronic diseases (out of 60) at each visit, analysed overall and within cardiovascular, neuropsychiatric, and musculoskeletal organ systems. Multivariate linear mixed models estimated the association between habitual fasting duration and the annual rate of multimorbidity accumulation, overall and stratified by age (<78 vs. ≥78 years).
Results
Compared with the lowest habitual fasting quartile (6–11.5 h), participants in the highest quartile (14–24 h) experienced steeper annual accumulation of total chronic diseases (β = 0.119; 95% confidence interval: 0.070, 0.167), cardiovascular diseases (0.022 [0.006, 0.038]), and neuropsychiatric diseases (0.019 [0.005, 0.033]), but not musculoskeletal diseases. The association with total chronic disease accumulation was apparent in adults aged ≥78 years (β = 0.099 [0.031, 0.168]) but absent in those <78 years (−0.009 [−0.078, 0.061]). Findings remained consistent across sensitivity analyses addressing reverse causation, measurement bias, and residual confounding.
Conclusion
In older adults, particularly the older old, longer habitual fasting duration was associated with faster chronic disease accumulation, suggesting it may be detrimental in advanced age.
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