Eating habits that leave long gaps between meals, such as intermittent fasting, may be linked to a faster buildup of chronic diseases in older adults, a new study has found. The tendency was especially pronounced among people aged 78 and over, where those with longer intervals between meals accumulated multiple chronic conditions more quickly over time.
Researchers at Sweden's Karolinska Institutet published the findings in the latest issue of the international journal Journal of Internal Medicine on the 22nd. The team analyzed data from 2,981 adults aged 60 and over who took part in the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). Participants had an average age of 74.3 at the start of the study, and their health was tracked for an average of 7.2 years and up to 15 years.
Clearest Difference Among Those Aged 78 and Over: Longer Meal Gaps, Faster Disease Buildup
Based on meal times recorded by the participants themselves, the researchers calculated the longest gap between meals in a day. They then divided participants into four groups by that interval — 6 to 11.5 hours, 11.5 to 12.75 hours, 12.75 to 14 hours, and 14 to 24 hours — and compared the onset and accumulation patterns of 60 chronic diseases.
The analysis showed that the group with the longest daily gap, 14 to 24 hours, developed multiple chronic conditions simultaneously at a faster rate over time than the group with a gap of 6 to 11.5 hours. The tendency held even after accounting for age and sex, as well as lifestyle, diet quality, and energy and protein intake.
By disease type, the difference was especially marked for cardiovascular and neuropsychiatric conditions. The longer an older adult's gap between meals, the faster those conditions accumulated over the follow-up period. In contrast, musculoskeletal diseases showed no clear difference by meal interval.
The difference was even sharper among those aged 78 and over. For people whose longest daily gap between meals was 14 to 24 hours, the trajectory of chronic disease accumulation rose more steeply than for the group with a gap of 6 to 11.5 hours. Among those under 78, by contrast, no statistically significant difference by meal interval was found.
"Hard to Apply the Same Approach as for Younger People": Fewer Chances for Nutrition Is the Problem
The researchers explained that the findings show it is difficult to apply directly to older adults the benefits of intermittent fasting, which have been established mainly among younger people.
As people age, their ability to digest food and absorb nutrients can decline, and if long periods of fasting compress the day's eating window too tightly, they may not take in enough of the nutrients they need. The reduced opportunity to consume protein, which is important for older adults, was cited as a particular concern.
With age, muscles may develop a phenomenon called anabolic resistance, in which they no longer respond as sensitively to dietary protein as they did in youth. For this reason, spreading protein intake across appropriate intervals may be more important than eating large amounts at once, and a persistently long gap between meals could lead to a loss of muscle mass, the researchers said.
The researchers stressed, however, that because this was an observational study, it cannot be concluded that long gaps between meals directly cause chronic disease. In other words, the findings should not be read to mean that intermittent fasting is unconditionally harmful to older adults.
"Especially in adults aged 78 and over, habitually long gaps between meals were found to be associated with a faster accumulation of chronic diseases," the researchers said. "In older age, there is a need to carefully examine the effects that prolonged fasting may have on health."
