Shorter Intervals Between Meals Linked to Higher Mortality

A shorter time interval of 4.5 hours or fewer between meals is associated with increased risk of all-cause mortality compared with longer intervals, according to a large, new prospective study that looked at both frequency of and intervals between meals in US adults 40 years of age and older.

The study also indicates that eating one meal per day — compared with three — is associated with higher mortality, both cardiovascular disease (CVD)-related as well as all-cause mortality, although when participants with diagnosed CVD and cancer at baseline were excluded from the analysis the statistical significance disappeared. 

As such, the findings may raise questions about the health benefits of limiting both the number of and interval between meals across the day, said lead author Yangbo Sun, MBBS, PhD, Department of Preventive Medicine, The University of Tennessee Health Science Center, Memphis.

“At a time when intermittent fasting is widely touted as a solution for weight loss, metabolic health, and disease prevention, our study is important for the large segment of American adults who eat fewer than three meals each day,” she said in a press release. “Our research revealed that individuals eating only one meal a day are more likely to die than those who had more daily meals.” 

“Among them, participants who skip breakfast are more likely to develop fatal cardiovascular diseases, while those who skip lunch or dinner increase their risk of death from all causes,” compared with those who eat three meals a day, noted Sun.

“Based on these findings, we recommend eating at least two to three meals spread throughout the day,” she said.

The findings were published in the Journal of the Academy of Nutrition and Dietetics, and the authors believe it is the first study to show that among people eating three meals per day, an average interval between two meals of 4.5 hours or less was associated with a higher risk of all-cause mortality.metabo

Reduced Interval Between Meals Overloads Metabolism

Sun and co-authors point out several possible reasons why skipping meals is a probable risk factor for disease and mortality. Firstly, they note food insecurity, which has been shown to be associated with higher CVD risk, adding that skipping breakfast, in particular, might be a behavioral marker for unhealthy dietary and lifestyle habits.

“However, the results remained significant after adjustment for food insecurity status, and a variety of dietary and lifestyle factors including smoking, alcohol use, physical activity levels, total energy intake, and overall diet quality, making them less likely explanations for the observed association between skipping meals and mortality,” they write.

They also highlight that skipping meals usually means eating meals with a larger energy load, which could aggravate the burden of glucose metabolism regulation, leading to subsequent metabolic deterioration.

“This could also explain the association between a shorter meal interval; for example,4.5 hours, and mortality, as a shorter waiting time in between meals also means a larger energy load in a given period of time.”

Senior investigator, Wei Bao, MD, PhD, epidemiologist from the University of Iowa, pointed out that, “Our findings are based on observations drawn from public data and do not imply causality. Nonetheless, what we observed makes metabolic sense.”

Nevertheless, they conclude: “These findings need replication and assessment in other populations.”

J Acad Nutr Diet. Published online August 10, 2022. Full text