Could Eating Only During Daytime Reduce Heart Risk Associated with Shift Work? Study Sheds Light - Video

A new study suggests that eating only during the daytime could help people avoid the health risks associated with shift work. Results are published in Nature Communications.

For the study, researchers enlisted 20 healthy young participants to a two-week in-patient study at the Brigham and Women’s Center for Clinical Investigation. They had no access to windows, watches, or electronics that would clue their body clocks into the time. The effect of circadian misalignment could be determined by comparing how their body functions changed from before to after simulated night work.

Study participants followed a “constant routine protocol,” a controlled laboratory setup that can tease apart the effects of circadian rhythms from those of the environment and behaviors. During this protocol, participants stayed awake for 32 hours in a dimly lit environment, maintaining constant body posture and eating identical snacks every hour. After that, they participated in simulated night work and were assigned to either eating during the nighttime or only during the daytime. Finally, participants followed another constant routine protocol to test the aftereffects of the simulated night work. Importantly, both groups had an identical schedule of naps, and, thus, any differences between the groups were not due to differences in sleep schedule.

The investigators examined the aftereffects of the food timing on participants’ cardiovascular risk factors and how these changed after the simulated night work. Researchers measured various cardiovascular risk factors, including autonomic nervous system markers, plasminogen activator inhibitor-1, and blood pressure.

Remarkably, these cardiovascular risk factors increased after simulated night work compared to the baseline in the participants who were scheduled to eat during the day and night.

“Our study controlled for every factor that you could imagine that could affect the results, so we can say that it’s the food timing effect that is driving these changes in the cardiovascular risk factors,” said Sarah Chellappa, MD, MPH, PhD, an associate professor at the University of Southampton, and lead author for the paper.

Reference: Chellappa, S.L., Gao, L., Qian, J. et al. Daytime eating during simulated night work mitigates changes in cardiovascular risk factors: secondary analyses of a randomized controlled trial. Nat Commun 16, 3186 (2025). https://doi.org/10.1038/s41467-025-57846-y