Researchers placed participants in a simulation that mimicked night shifts, and participants either had meals during the day only, or had meals during both daytime and nighttime. There were two meal timing groups: the daytime and nighttime meal control group, and the daytime-only meal intervention group.
Those who ate during both day and night were found to undergo a 26 percent increase in depression mood levels and a 16 percent rise in anxiety mood levels relative to a baseline (which was the first day of the study), while those in the daytime group did not.
The study supports using “the timing of food intake as a novel strategy to potentially minimize mood vulnerability” in those engaged in shift work, jet lag, or suffering from circadian rhythm disorders, according to one of the authors, Frank A. J. L. Scheer, director of the Medical Chronobiology Program in the Brigham’s Division of Sleep and Circadian Disorders.
“Future studies in shift workers and clinical populations are required to firmly establish if changes in meal timing can prevent their increased mood vulnerability. Until then, our study brings a new ‘player’ to the table: The timing of food intake matters for our mood,” Scheer added.
According to the U.S. Bureau of Labor Statistics, around five percent of American adults work in the evening, while permanent night workers and workers with irregular schedules make up a further four percent. Furthermore, another four percent are rotating shift workers. In total, this adds up to 15.5 million people.
Even without accounting for different mealtimes, researchers also noted that shift workers have a “25 to 40 percent higher risk of depression and anxiety.”
Hence shift workers, and others suffering from “circadian disruption,” may benefit from a “meal timing intervention,” said Sarah Chellappa, a co-author of the study.
Furthermore, Chellappa added that meal timing intervention can be a strategy to help “optimize sleep and circadian rhythms [that] may help promote mental health.”
“Meal timing is emerging as an important aspect of nutrition that may influence physical health,” said Chellappa. “But the causal role of the timing of food intake on mental health remains to be tested. Future studies are required to establish if changes in meal timing can help individuals experiencing depressive and anxiety [or] anxiety-related disorders.”
The study enrolled 19 participants. Its findings were published on Sept. 12 in the Proceedings of the National Academy of Sciences.