How Meal Timing Affects Heart Health, According to New Research

We've been independently researching and testing products for over 120 years. If you buy through our links, we may earn a commission. Learn more about our review process. We hear a lot about the importance of keeping a consistent sleep schedule, and for good reason. Sleeping in for a few extra hours on the weekend or staying up much later than usual can throw off your body's internal clock, something researchers often refer to as 'social jet lag.' But if consistency matters for sleep, could it matter for eating too? That's the question behind a that looked at what researchers call 'eating jet lag,' or how much someone's mealtimes shift between weekdays and weekends. Think about your own routine. Maybe you typically eat breakfast at 8 a.m. during the week, but on Saturday you sleep in and don't eat until closer to noon. That three- or four-hour difference is the kind of shift researchers were interested in. So how common are these shifts, and could they connect to heart health? Here's what the study found. What the research shows Researchers used data from 104,806 adults in France and compared when people ate on weekdays versus weekends. They then followed participants for a median of 8.1 years to see how these eating patterns related to cardiovascular health. The findings were more striking among men. For every additional hour of difference in meal timing between weekdays and weekends, men had a 14% higher risk of cardiovascular disease and a 21% higher risk of coronary heart disease. The associations remained significant even after researchers adjusted for diet quality, bedtime, total sleep time, and social jet lag. In other words, the relationship wasn't simply explained by people with more irregular meal schedules also having poorer diets or less consistent sleep. This was an observational study, so we can't say that shifting your mealtimes causes heart disease. People who have more irregular schedules may also differ from those with more consistent schedules in ways that are difficult to fully capture in a study. And the findings weren't the same for everyone. The association was not statistically significant in women. The researchers note that men generally have a higher absolute risk of cardiovascular events than women, which could be one reason the results differed between the two groups. Lifestyle, biological rhythms, and work or social schedules could also affect both when people eat and their cardiovascular risk. So, while the findings in men are certainly worth paying attention to, they don't give us a simple answer about whether meal-timing consistency affects heart health in everyone. Does diet play a role? It would be easy to assume that people with irregular eating schedules simply have less healthy diets. But the link remained among men even after the researchers accounted for diet quality. Of course, that doesn't mean what you eat isn't important. We have plenty of evidence that overall diet quality matters for heart health. Instead, the findings suggest that when you eat could be another factor to consider alongside diet quality, sleep, physical activity, and other lifestyle habits. This isn't the only research on meal timing Meal timing is getting more attention in nutrition research, particularly as scientists learn more about the connection between our eating patterns and our circadian rhythms. Our bodies have internal clocks that help coordinate things like sleep, hormones, and metabolism. And food is one of the signals that interacts with those rhythms. Another recent study published in the also examined meal timing and health outcomes, adding to the growing research on not just what we eat, but when we eat. That study found that people who ate their first meal later in the day and their last meal very late at night had a higher risk of dying overall, as well as a higher risk of dying from cardiovascular disease. Taken together, this research doesn't mean you need to eat breakfast, lunch, and dinner at exactly the same time every day. But it does give us another reason to think about the patterns and rhythms around eating, not just the food on our plate. The bottom line This study does not mean you need to follow a rigid meal schedule. Real life doesn't work that way; work schedules change, and weekends are different from weekdays. I don't think occasionally sleeping in or having a late dinner will completely throw things off. What may be more interesting to pay attention to is the pattern over time. If your meal schedule consistently shifts by several hours every weekend, that may be different from occasionally eating breakfast later on a Saturday. You don't need to eat at exactly the same times every day, but keeping your meals relatively consistent—along with eating well, exercising, and prioritizing sleep—may be worthwhile. Why trust Good Housekeeping? Stefani Sassos, M.S., R.D.N., C.D.N., is the director of the Good Housekeeping Institute Nutrition & Fitness Lab, where she oversees all nutrition content, product testing, and evaluation. A registered dietitian, Stefani stays up to date on the latest scientific research to provide evidence-based guidance on diet, wellness, and healthy living.