A study led by researchers at President Mis Young shows that when it comes to cardiovascular health, food timing may be greater than sleep time
Many studies have shown that night shift work is associated with serious health risks, including the heart. But a new study by large-scale President Yang shows that eating during the day can help people avoid health risks associated with shift work. The results are published in Natural Communication.
“Our previous research shows that misalignment of the day and night – the error of our behavioral cycle relative to the internal human clock increases cardiovascular risk factors,” said Dr. Frank Ajl Scheer, professor of medicine and director of the Medical Biology Program, a founding member of the Brigham and Women’s Hospital. “We want to understand what steps can be taken to reduce this risk, and our new research suggests that food timing may be the goal.”
Animal studies show that keeping food timing consistent with internal clocks can mitigate the health risks of staying awake during typical rest periods, prompting Scheer and his colleagues to test the concept in humans.
In this study, the researchers invited 20 healthy young participants to conduct a two-week hospitalization study at Brigham Young and Women’s Clinical Research Center. They cannot access windows, watches or electronic devices that can make their body clocks to the clock at that time. The effects of circadian misalignment can be determined by comparing how their body functions change from previous nighttime work to previous changes.
Study participants followed a “constant routine protocol,” a controlled lab setup that mocked the effects of circadian rhythms with the rhythm of environment and behavior (e.g., sleep/wake, light/dark mode). In this protocol, participants remained awake in a dim environment for 32 hours, maintaining their body in a continuous posture and the same snacks every hour. After that, they participated in simulated night work and were assigned to feed at night (like most night workers) or only during the day. Finally, participants followed another constant routine protocol to test the sequelae of simulated nighttime work. Importantly, the nap schedules were the same for both groups, so no difference between the two groups was due to differences in the sleep schedule.
Investigators examined the post-effect period of food timing for participants’ cardiovascular risk factors and how they change after simulated nighttime work. The researchers measured a variety of cardiovascular risk factors, including autonomic nervous system markers, plasminogen activator inhibitor 1 (increasing the risk of blood clots), and blood pressure.
It is worth noting that these cardiovascular risk factors increased after simulated nighttime work compared to participants who planned to eat during the day and night. However, among the study participants, the risk factors remained the same, and they only ate during the day, even if they had no difference between the two groups and nothing, when They ate.
Limitations of the study include the small sample size, although typical sizes for such highly controlled and intensive randomized controlled trials. Furthermore, because the study lasted for two weeks, it may not reflect the chronic risk of eating at night versus daytime.
One advantage is that participants’ sleep, diet, exposure, body posture, and activity schedules are strictly controlled.
“Our study controls every factor you can imagine that might affect the outcome, so we can say that the food timing effects are driving these changes in cardiovascular risk factors,” said Sarah Chellappa, associate professor at the University of Southampton, MPH, MPH, MPH, MPH, PHD.
Scheer and Chellappa said that while further studies are needed to show the long-term health effects of daytime and nighttime diets, the results indicate “promising” and suggest that people can improve their health by adjusting their food timing. They added that avoiding or restricting nighttime diets may make nighttime workers, those experiencing insomnia or sleep disorders, those with variable sleep/wake cycles, and those who travel frequently in time zones.
Author identity: In addition to Scheer, the authors of VW Brigham Young include Lei Gao, Jingyi Qian, Nina Vujovic, Peng Li and Kun Hu.
Disclosure: Scheer has served on the Board of Directors of the Sleep Research Society and has received consultation fees from the University of Birmingham and the University of Alabama.
funds: This study was funded by grant numbers NIH R01HL118601 (ClinicalTrials.gov number: NCT02291952), 1UL1TR001102 and 1UL1TR002541-01. Funders have no role in research design. In the collection, analyze or interpret the data; in the book writing the manuscript, or decide to publish it.
Cited papers: Chellappa SL wait. “Daytime feeding in simulated night work alleviates changes in cardiovascular risk factors: a secondary analysis of randomly controlled Sanya stateltransparent Natural Communications doi:10.1038/s41467-025-57846-y
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