What you eat clearly matters for health, but a large U.S. study suggests that when you eat may matter too.
Researchers found that adults who ate their first meal later in the day, or their last meal very late at night, had a higher risk of dying during follow-up.
The research analyzed more than 30,000 Americans aged 40 and older. The findings were published in the European Journal of Clinical Nutrition in 2026.
Scientists have long known that the human body follows a roughly 24-hour internal clock. This system, known as the circadian rhythm, helps control sleep, hormone release, body temperature, digestion, blood sugar, and many other biological processes.
Light is one of the strongest signals that keeps this internal clock on schedule, but food may also provide important timing information. This has led to growing interest in chrononutrition, the study of how the timing of meals may interact with the body’s natural daily rhythms.
Modern eating patterns can be very different from traditional schedules. Many people skip breakfast, work irregular hours, snack late at night, or eat their final meal shortly before going to bed.
Researchers wanted to know whether these habits were connected with long-term health and survival. They used information from 31,044 adults who took part in the U.S. National Health and Nutrition Examination Survey between 1999 and 2018.
Participants provided detailed information about what and when they ate during 24-hour periods. The researchers then linked those records with national death data and followed participants through the end of 2019.
The average follow-up was about 8.6 years. During that period, the team examined deaths from all causes as well as deaths related to cardiovascular disease, including heart disease and stroke.
The timing of the first meal showed a clear pattern. People who ate their first meal between 7 and 8 a.m. were used as the comparison group because this period was associated with the lowest risk.
Those who first ate between 8 and 10 a.m. had about a 10% higher risk of death from any cause. For people who waited until between 10 a.m. and noon, the increase was about 19%.
The association became stronger among people whose first meal came after noon. They had a 29% higher risk of death from any cause than people who ate between 7 and 8 a.m., according to the study.
Some cardiovascular results were also striking. Having the first meal between 10 a.m. and noon was associated with a 59% higher risk of stroke-related death, while eating the first meal after noon was linked to a 43% higher risk of death from heart disease.
The researchers also examined the timing of the final meal of the day. The lowest risk appeared among people who ate their last meal between 7 and 8 p.m.
Eating before 7 p.m. was associated with a 13% higher risk of death from any cause compared with that period. The highest risks appeared among people who ate after midnight.
A final meal after midnight was linked to a 27% higher risk of death from any cause and a 51% higher risk of cardiovascular death. These results suggest that extremely late eating may be particularly important to study further.
The researchers also estimated life expectancy beginning at age 50. Compared with eating the first meal between 7 and 8 a.m., having it between 8 and 10 a.m. was associated with about 0.9 fewer years of expected life.
For those whose first meal came after noon, the estimated difference was 2.5 fewer years. Eating the last meal after midnight was associated with about 2.4 fewer years compared with having it between 7 and 8 p.m.
These numbers may sound dramatic, but they should not be interpreted as a countdown for an individual person. They are statistical estimates based on patterns across a large population, not predictions of exactly how long any one person will live.
There are several possible reasons meal timing could matter. Eating at times that conflict with the body’s internal clock may affect blood sugar control, insulin, fat storage, inflammation, and other processes connected with cardiovascular and metabolic health.
However, another explanation is also possible. People who eat very late or skip morning meals may differ in many other ways, including work schedules, sleep patterns, income, existing illness, smoking, exercise, and overall diet quality.
This is the most important limitation of the research. The study was observational, so it found associations but cannot prove that changing breakfast or dinner time will make someone live longer.
Meal timing was also based on dietary records from limited periods, which may not perfectly represent a person’s eating habits over many years. Future studies will need repeated measurements and controlled trials to determine whether deliberately changing meal schedules improves health.
Still, the study strengthens interest in looking beyond calories and nutrients when thinking about nutrition. The timing and regularity of meals may eventually become another part of healthy eating advice, especially if future research confirms a direct effect.
For now, the findings should be seen as useful evidence rather than a strict rule that everyone must eat at exactly 7 a.m. and 7 p.m. A healthy diet, regular activity, adequate sleep, not smoking, and appropriate medical care remain far better established ways to protect long-term health.
Source: European Journal of Clinical Nutrition.
