A new study from Mass General Brigham suggests that when you eat might matter more than when you sleep when it comes to protecting your heart. The researchers found that eating only during the daytime could reduce heart-related risks, even in people working night shifts—a group known to face higher health risks.
The study, published in Nature Communications, looked at how the timing of meals affects cardiovascular health during night work.
It builds on previous research showing that a mismatch between our behavior—like sleep and eating patterns—and our internal body clock (circadian rhythm) can increase the risk of heart disease. This mismatch, known as circadian misalignment, is common among night-shift workers.
Led by Dr. Frank Scheer and Dr. Sarah Chellappa, the team conducted a highly controlled two-week in-patient study with 20 healthy young adults. During this time, participants had no access to clocks, windows, or electronic devices, so their bodies couldn’t rely on external cues to tell what time it was.
The participants were put through what’s called a “constant routine protocol.” This meant staying awake in dim light for 32 hours, maintaining the same posture, and eating identical snacks every hour. This setup allowed the researchers to isolate the effects of internal body rhythms from other influences like sleep or light exposure.
Next, the participants experienced a simulation of night shift work. Half of the group was allowed to eat during both day and night (as most night shift workers do), while the other half was limited to eating only during the daytime—even though they were awake at night.
After this simulated night work, the researchers again tested their cardiovascular health. They measured blood pressure, blood clot risk (through a marker called plasminogen activator inhibitor-1), and autonomic nervous system activity (which affects heart rate and stress response).
The results were striking. The group that ate during both day and night showed increased cardiovascular risk factors after the night work. Meanwhile, the group that only ate during the day showed no increase in these risk markers—even though both groups ate the same amount and type of food and had the same sleep schedules.
The researchers believe that meal timing may help “reset” the body’s clock or reduce stress on biological systems that are disrupted by staying awake at night. Importantly, this suggests a relatively simple and low-cost strategy for reducing health risks among shift workers or people with irregular schedules.
While the study was small—typical for such tightly controlled lab studies—it offers strong evidence because of its careful design. All other possible factors that could affect results, like light exposure, physical activity, sleep, or food type, were kept exactly the same.
Still, the researchers note that more studies are needed to understand long-term effects and whether these findings apply to larger and more diverse populations. But the early results are promising.
They suggest that avoiding eating at night—even if you’re awake—might be a good step for protecting your heart. This could be especially helpful for night-shift workers, people with insomnia, or anyone who frequently travels across time zones.
In short, your body might thank you for sticking to daylight meals—even when your sleep schedule isn’t so regular.
If you care about heart health, please read studies that apple juice could benefit your heart health, and Yogurt may help lower the death risks in heart disease.
For more information about health, please see recent studies that Vitamin D deficiency can increase heart disease risk, and results showing Zinc and vitamin B6 linked to lower death risk in heart disease.
The research findings can be found in Nature Communications.
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