Meal timing affects longevity

The study used data from 31,044 adult residents of the United States aged 40 and over who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. The timing of meals was recorded using 24‑hour food diaries; this approach is more accurate than relying on participants’ recollections. These data were then compared with the National Mortality Index: the participants were followed for an average of 8.6 years, and the study ended on December 31, 2019. During this period, cases of death from all causes were recorded, as well as deaths specifically from heart disease and stroke.

The researchers chose breakfast between 7 and 8 a.m. as the key reference point. Compared to this option, a later first meal was associated with an increased risk. If the first meal was consumed between 8 and 10 a.m., the risk of death from any cause increased by 10 %. When shifted to the interval from 10 a.m. to noon, the risk increased to 19%, and the likelihood of a stroke nearly doubled (by 59%). For those who skipped breakfast and ate their first meal after noon, the overall risk was 29% higher, and the risk of heart disease was 43% higher.

As for dinner, the scientists identified the optimal time as between 7 and 8 p.m. Eating before 7 p.m. was associated with a 13 % increase in the risk of death, and eating after midnight turned out to be particularly dangerous: overall mortality increased by 27 %, and mortality from heart disease — by 51 %.

The influence of meal timing was also evident in life expectancy indicators. Among participants over 50 years of age, having breakfast between 8 and 10 a.m. was associated with a reduction in life expectancy by 0.9 years, while having the first meal after noon was associated with a reduction of 2.5 years compared to the baseline. For dinner, deviations from the golden hour also had significance: eating before 7 p.m. correlated with a loss of 1.2 years of life, and after midnight — with a loss of 2.4 years.

Scientists say that this is an observational study, meaning it shows a connection but does not prove a cause‑and‑effect relationship. Nevertheless, the results indicate the importance of chrononutrition — a field that studies how the timing of meals interacts with the body’s circadian rhythms and affects metabolism and health.

Given that today almost every fifth adult American skips breakfast, and about 60 % eat late in the evening, the issue of eating patterns is becoming particularly relevant. The authors believe that taking into account the optimal timing of meals, along with the quality of the diet, could become an important strategy for improving public health.