Stopping meals at least three hours before bed and slightly extending the overnight fast may improve blood pressure patterns and blood-sugar control, according to a small new study from researchers at Northwestern University.
The study, published in Arteriosclerosis, Thrombosis, and Vascular Biology, a journal of the American Heart Association, followed 39 adults ages 36 to 75 who were overweight or obese and at elevated risk for cardiometabolic disease. Participants did not reduce calories. Instead, the intervention group fasted 13 to 16 hours overnight and stopped eating at least three hours before bedtime, while the control group maintained their usual 11- to 13-hour overnight fast.
Nighttime blood pressure dipped 3.5% more in the sleep-aligned fasting group compared with controls, and heart rate dipped 5% more. During the day, participants also showed improved glucose response, suggesting more efficient insulin release.
“It’s not only how much and what you eat, but also when you eat relative to sleep that is important for the physiological benefits of time-restricted eating,” said Dr. Phyllis Zee, chief of sleep medicine at Northwestern’s Feinberg School of Medicine.
Rather than focusing on aggressive fasting windows or calorie restriction, the study anchored the eating window to the body’s natural sleep-wake rhythm. Both groups dimmed lights three hours before bedtime to reduce circadian disruption, but only the intervention group extended their fast and avoided late meals.
Healthy cardiovascular systems typically show a clear day-night rhythm, with blood pressure and heart rate rising during the day and falling at night. Blunted nighttime dipping has been linked to higher cardiovascular risk. In this study, aligning meals with sleep appeared to strengthen that rhythm.
The intervention also had a nearly 90% adherence rate, suggesting that stopping dinner earlier may be more sustainable for many people than more restrictive diet strategies.
Still, the findings should be interpreted cautiously. The study included only 39 participants and lasted 7.5 weeks. About 80% of the intervention group were women, and all participants were middle-aged or older adults with overweight or obesity. The study was not designed to assess long-term outcomes such as heart attacks, diabetes incidence or weight loss.
The results add to growing research suggesting that timing may influence metabolic health, particularly in relation to sleep and circadian rhythms. They do not suggest that everyone needs to adopt a 16-hour fast, nor do they show that meal timing replaces other proven lifestyle strategies such as improving diet quality, physical activity or sleep duration.
For readers trying to simplify health decisions, the takeaway is modest but practical: consistently finishing dinner earlier and avoiding late-night eating may support natural cardiovascular and metabolic rhythms, especially for those already at higher cardiometabolic risk.
As the researchers note, larger multi-center trials are needed to determine how broadly these findings apply and whether the benefits persist over time.
This research was funded by the National Heart, Lung, and Blood Institute and the National Institute on Aging, both part of the National Institutes of Health.