A large study of over 50,000 Americans found that the timing of meals and snacks throughout the day may be connected to how long people live. Researchers discovered that eating most of your food late at night or very early in the morning was linked to higher risks of heart disease and cancer deaths. The study also found that people who ate their meals later in the day had a shorter eating window (the time between their first and last meal). These findings suggest that when you eat—not just what you eat—could be important for your long-term health.

The Quick Take

  • What they studied: Whether the times of day people eat their meals and snacks are connected to their risk of dying from heart disease or cancer
  • Who participated: Over 50,000 American adults aged 20 and older who participated in national health surveys between 1999 and 2020. The group included people of different ages, races, and income levels
  • Key finding: People who ate a lot of food late at night (10pm-2am) or very early in the morning (2-6am) had higher risks of dying from heart disease or cancer compared to those with more typical eating schedules. Eating just one hour later than usual was connected to an 8-9% higher risk of heart disease death
  • What it means for you: Your eating schedule might affect your health risks, but this study shows a connection, not proof that late eating causes disease. If you eat most of your meals late at night, talking to a doctor about adjusting your eating times could be worth considering

The Research Details

Researchers looked at information from the National Health and Nutrition Examination Survey, a program that tracks what Americans eat and their health outcomes over time. They collected data from 1999 through early 2020 and followed people’s health records through the end of 2019 to see who passed away and from what causes.

Participants reported everything they ate and drank over 24-hour periods. Researchers then organized this information by time of day: morning (6-10am), noon (10am-2pm), afternoon (2-6pm), evening (6-10pm), midnight (10pm-2am), and overnight (10pm-6am). They looked at patterns in when people ate carbohydrates, proteins, fats, and different food groups like grains, fruits, and dairy products.

The researchers then used statistical methods to see if the timing of eating was connected to death rates from different causes, while accounting for other factors that affect health like age, weight, and smoking.

This approach is important because it shows real-world eating patterns of actual Americans rather than studying people in controlled lab settings. By following people over many years and tracking actual health outcomes, researchers could identify patterns that might affect how long people live. The large number of participants makes the findings more reliable than smaller studies

This study has several strengths: it included a very large, diverse group of Americans, tracked them over 20+ years, and used actual death records. However, it’s important to know that this study shows associations (connections) rather than proof that eating timing causes health problems. People who eat late at night might have other lifestyle differences that affect their health. The study relied on people remembering what they ate, which can be inaccurate. Additionally, the study couldn’t account for all possible factors that influence health and lifespan

What the Results Show

The study found clear patterns in when Americans eat. Most people (about 32%) eat their largest meals in the evening between 6-10pm. About 25% of their daily food comes around noon, 20% in the afternoon, 14% in the morning, and only 6% overnight. Interestingly, between 23-28% of Americans eat something between 10pm and 2am.

The most striking finding was about late-night eating: people who shifted 5% of their daily calories to midnight eating had a 9% higher risk of dying from heart disease. This effect was especially strong when the late-night eating involved carbohydrates. Similarly, eating 5% of daily calories very early in the morning (2-6am) was linked to a 22% higher cancer death risk, particularly when those calories came from protein.

Another important finding involved overall eating timing: people who delayed when they stopped eating (fasting time) or delayed their average eating time by just one hour had an 8-9% higher risk of heart disease death. For example, if someone normally stopped eating at 8:30pm but started eating at 9:30pm instead, this one-hour delay was connected to increased health risks.

The study revealed that eating patterns varied by demographic groups. Men, Black Americans, and people with lower incomes were more likely to eat significant amounts of food late at night and had later average eating times. Most Americans eat within a roughly 12-hour window (from about 8:30am to 8:40pm), but this varied among different groups. The timing of different food groups also varied: whole grains were more commonly eaten in the morning, while fruits, eggs, and dairy were more evenly spread throughout the day

Previous research has suggested that eating timing affects metabolism and health, but this is one of the first large studies to examine actual eating patterns across the entire US population and connect them to real health outcomes. Earlier studies were often smaller or conducted in controlled settings. This research supports growing evidence that circadian rhythms (your body’s internal clock) may influence how your body processes food and affects disease risk

This study shows connections between eating timing and health risks, but cannot prove that late eating causes disease. People who eat late might also have other unhealthy habits. The study relied on people remembering one or two days of eating, which may not represent their typical patterns. The researchers couldn’t account for all factors affecting health, such as sleep quality, stress, or exercise. Additionally, the study was observational, meaning researchers watched patterns rather than randomly assigning people to different eating schedules

The Bottom Line

Based on this research, eating your meals within a consistent, earlier time window (finishing by 8-9pm rather than midnight or later) appears to be associated with lower health risks. This is a moderate-confidence recommendation based on observational evidence. Avoiding large meals or significant snacking between 10pm and 6am may be beneficial. However, these are associations, not proven causes, so individual circumstances vary

This research is most relevant for adults who regularly eat late at night or have very late eating windows. People concerned about heart disease or cancer risk may want to consider their eating timing. Those with shift work or irregular schedules should be aware that very late eating may carry health risks. However, this study doesn’t apply to children, pregnant women, or people with certain medical conditions that require specific eating schedules. If you have health concerns, consult your doctor before making major changes

Changes in eating timing might affect health markers like blood pressure or cholesterol within weeks to months, but the connection to actual disease risk and lifespan would take years to observe. Don’t expect immediate results, but consistency over months and years is what likely matters for long-term health benefits

Want to Apply This Research?

  • Track your first meal time, last meal/snack time, and calculate your eating window (hours between first and last intake). Aim to narrow this window and move it earlier, such as eating between 7am-8pm instead of 9am-11pm. Monitor this weekly to see if you can consistently finish eating by 8-9pm
  • Set a personal eating cutoff time (like 8pm) and use app reminders to help you stop eating by that time. If you currently eat late-night snacks, gradually shift them earlier or replace them with water or herbal tea. Start by moving your eating window 30 minutes earlier each week until you reach your goal
  • Log eating times for 2-4 weeks to establish your baseline pattern, then set a goal to narrow your eating window by 1-2 hours. Track compliance weekly and note any changes in how you feel (energy, sleep quality, digestion). Review monthly to see if earlier eating times become consistent habits

This study shows associations between eating timing and health outcomes but does not prove that changing eating times will prevent disease or extend lifespan. Individual health outcomes depend on many factors beyond eating timing, including genetics, overall diet quality, exercise, sleep, and stress. Before making significant changes to your eating schedule, especially if you have existing health conditions, take medications, or have a history of eating disorders, consult with your healthcare provider or registered dietitian. This information is for educational purposes and should not replace professional medical advice.