Longer fasting linked to accelerated chronic disease in the elderly, study suggests

A Swedish study has linked older adults who have longer intervals between meals to accumulate chronic diseases more quickly over time, compared to those with shorter intervals. 

The researchers, from Karolinska Institutet, found that the association was most noticeable among people aged 78 and above. They used data from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) in Stockholm, including 2,981 participants aged 60 years or older when the study period began.

The team spotted a need to investigate the impacts of fasting in the older population, as they argue that most current scientific research focuses on younger people.

“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,” says study last author Adrián Carballo Casla, postdoctoral researcher at the Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet.

Observing the older generation

The SNAC-K participants self-reported information on when they typically ate during 24 hours, and were followed up after 15 years.

Based on the SNAC-K data, the new study, published in the Journal of Internal Medicine, found that having longer intervals between meals was associated with more rapidly accumulating chronic diseases. Those who waited 14–24 hours in between meals did so much quicker than those who waited 6–11.5 hours in between meals.

Having longer intervals between meals was associated with more rapidly accumulating chronic diseases.The researchers note that the link was found for cardiovascular and neuropsychiatric diseases, but not for musculoskeletal diseases. Meanwhile, they emphasize that the observational study cannot determine cause and effect.

The authors note that fasting has been shown to be beneficial among younger populations, while scientific findings for older populations are lacking. There may also be differences among the lower and higher spans of the older population due to nutritional and physiological challenges associated with fasting that could impact health.

The study references previous observational studies in community-dwelling older adults that have shown that longer habitual fasting times are linked to adverse metabolic biomarkers and poorer lower extremity function.

“More broadly, a recent systematic review has emphasized that, although intermittent fasting can produce metabolic benefits in some contexts, robust evidence in humans is scarce and excessive fasting may entail health risks, underscoring the need for caution in older adults,” reads the study.

Science on fasting

Intermittent fasting has gained popularity in recent years for its metabolic benefits and rapid weight loss, and interest has been driven partly by social media influencers. Fasting has been praised and questioned in prior studies, finding different results in terms of health benefits and risks between population groups.

A study published earlier this year suggested that intermittent fasting is unlikely to lead to weight loss in obese and overweight adults. The researchers compared intermittent fasting to following traditional dietary advice and making no changes. It did not appear to have a clinical effect on weight loss in either comparison, a finding that multiple experts disagreed on. 

Fasting has been praised and questioned in prior studies.One author of the study said intermittent fasting may be a reasonable weight loss option for some people, but cautioned that the current evidence “doesn’t justify the enthusiasm” around the habit on social media.

Another study found intermittent fasting to have potential benefits for polycystic ovary syndrome (PCOS), now renamed polyendocrine metabolic syndrome (PMOS), as weight loss decreased testosterone levels among women with the condition.

A separate small-scale pilot study proposed that intermittent fasting may reduce dementia risk by restricting the eating window to fewer hours of the day. Overweight or obese older women who limited their daily eating window instead of just reducing their calorie intake displayed modest cognitive improvements in the study while participating in a weight loss program. 

In other women’s health news, Nutrition Insight previously sat down with the creator of the Cycle Syncing Method, who told us that dietary patterns, including fasting, must be adapted to a woman’s natural cycle, as it may be beneficial during some weeks of the month, while in other phases it may disrupt overall health.