When it comes to dinner, many people focus on the type and portion size of food, but the timing of the meal often receives less attention. However, increasing research indicates that the timing of dinner may play a significant role in how the body processes food, making an earlier dinner a potentially beneficial option for metabolic health and sleep. According to Frank Scher, director of the Medical Chronobiology Program at Brigham and Women's Hospital, the body operates on a biological clock that regulates many of its functions.
A study conducted by Dr. Daisy Duan from Johns Hopkins University School of Medicine found that eating the same meal at different times can have varying effects on the body. In the study, 20 healthy young adults consumed the same meal at 6 pm and 10 pm, and the results showed that eating at a later hour led to higher blood sugar levels and reduced the body's ability to process fat compared to eating at an earlier hour.
The hormone melatonin, which increases at night in preparation for sleep, may be a contributing factor to the differences in how the body responds to food at different times. Scher suggests that as the body prepares for sleep, its ability to process glucose changes, and eating a late meal may be more challenging for metabolic processes. Additionally, experiments conducted by Scher’s team found that eating at a later hour may be associated with increased hunger and decreased calorie burn.
While the results suggest that eating a late dinner may have negative effects, researchers caution that it is not a definitive cause of obesity or diabetes in everyone. Many studies have been conducted in controlled laboratory settings over short periods, which may not accurately reflect real-life situations. However, Duan notes that repeatedly eating at a late hour may be linked to metabolic problems over time.
The impact of dinner timing may extend beyond metabolism and weight, as it may also affect sleep quality. Research by Duan found that individuals who stopped eating earlier in the evening tended to have longer sleep durations compared to those who continued eating until midnight. A 2024 study also found an association between late eating and increased risk of mortality, although such observational findings do not establish a direct causal link.
While there is no single ideal dinner time that suits everyone, experts generally agree that avoiding large meals close to bedtime is a more suitable option for metabolic health. Duan recommends leaving at least two hours between the last meal and bedtime, while Colin Webb from New York University's Grossman School of Medicine suggests aiming for dinner between 5 pm and 7 pm as a practical goal.
To make dinner earlier, individuals can start with small steps, such as gradually adjusting their dinner time rather than making drastic changes. Eating balanced and nutrient-rich meals earlier in the day can also help reduce hunger in the evening. Establishing a consistent kitchen closure time and gradually adjusting it to an earlier hour can also be beneficial, as Duan notes that changing habits begins with small, achievable steps.
Key points
- Eating dinner at a later hour can lead to higher blood sugar levels and reduced ability to process fat.
- Avoiding large meals close to bedtime may be beneficial for metabolic health.
- Establishing a consistent and earlier dinner time may help improve sleep quality.
