Por the French, meals are serious business. According to OECD figures, we spend an average of 2.13 hours each day eating and drinking. That’s twice as long as Americans and forty minutes longer than other OECD countries. But be careful not to work at any time: according to a recent study, mealtimes have a direct effect on mental health.
In the United States, researchers at Brigham and Women’s Hospital in Boston have found that eating during the day can benefit mental health. Conversely, taking meals at night – for example for workers on staggered schedules – would increase the risk of depression and anxiety. In detail, the scientists found that between daytime and nighttime meals, depressed mood levels increased by 26% and anxious mood levels by 16%. Conversely, those who only eat their meals during the day did not report this phenomenon. These findings were published in the Proceedings of the National Academy of Sciences.
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The importance of the circadian rhythm
This study involved 19 people, all of whom underwent forced desynchronization with dim light for four 28-hour periods. In the end, the cycles were totally reversed. Two groups were formed and the meals taken at different times. The team assessed depressed and anxious mood levels hourly. “Our results provide evidence for the importance of meal timing. Timing of food intake represents a new strategy to potentially minimize mood vulnerability in people with circadian misalignment such as shift workers, those with jet lag or circadian rhythm disorders,” explained the author of this study, Frank AJL Scheer, director of the medical chronobiology program.
Circadian rhythm, what are we talking about? In the human body, biological functions are regulated by the circadian system based on a 24-hour rhythm. This rhythm is defined by the alternation between the phases of wakefulness and sleep. By working staggered hours, this biological clock becomes desynchronized and is no longer in phase. For the future, the team of scientists wishes to carry out other studies to establish the existence of a link between the change in meal times and changes in mood. “Our study provides new data: the timing of food intake is important for our mood,” adds Franck AJL Scheer.
Firefighters, workers, certain health professionals, etc., the list of night workers is long. For them, there is a discrepancy between the circadian rhythm and certain daily behaviors. “Our findings open the door to a new sleep/circadian behavior strategy that could also benefit people with mental health conditions. Our study adds to a growing body of evidence showing that strategies that optimize sleep and circadian rhythms can help promote mental health,” says Sarah L. Chellappa, who completed work on this project at Brigham.
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In France, workers with staggered hours are not uncommon. According to the Department of Research, Studies and Statistics (Dares), in its 2018 study, at least 44% of French people work according to an “atypical” schedule. Among them, 9% work at night. As the National Institute for Research and Security (INRS) reminds us, the risks associated with this desynchronization of the circadian rhythm are numerous, such as sleep disorders or vigilance. Other effects are likely: weight gain or the appearance of certain coronary diseases, which can increase the risk of heart attack. This situation is all the more delicate for pregnant women: “Shift and/or night work would increase the risk of spontaneous abortion, premature delivery and intrauterine growth retardation”, also alerts the INRS.