Early dinner improves blood sugar levels and boosts metabolism: Study
Japan: Early dinner at (at 18:00) versus late dinner (at 21:00) has a positive effect on blood sugar level fluctuation and substrate oxidation, according to a recent study in the journal Nutrients.
Previous studies have shown that eating dinner late promotes metabolic dysfunctions including glucose metabolism. In contrast, early time-restricted eating (ETRE) or intermittent fasting which involves earlier consumption of the last meal of the day which lengthens the period of time that elapses before the next meal, appears to have a positive effect on blood pressure, insulin sensitivity, blood sugar, and triglycerides, especially in obese or overweight people. In animal models, biological effects of ETRE, independent of energy restriction have also been demonstrated.
The health benefits of intermittent fasting seems to result from more than factors known currently including weight loss and free-radical production, but the exact mechanism is still not known.
Against the above background, Kaho Nakamura, Prefectural University of Kumamoto, Kumamoto, Japan, and colleagues aimed to examine whether mild early time-restricted eating (eating dinner at 18:00 vs. at 21:00) improves 24-h blood glucose levels and postprandial lipid metabolism in healthy adults in a randomized crossover study.
The study included 12 participants (10 females and 2 males). Two different conditions were tested: eating a late dinner (at 21:00) or an early dinner (at 18:00). During the experimental period, blood glucose levels were evaluated by each participant wearing a continuous blood glucose measuring device.
Using the indirect calorimetry method, metabolic measurements were performed on the morning of day 3. The study was conducted over three days; day 1 was excluded from the analysis to adjust for the effects of the previous day's meal, and only data from the mornings of days 2 and 3 were used for the analysis.
Key findings of the study include:
- Significant differences were observed in mean 24-h blood glucose levels on day 2 between the two groups.
- There was a significant decrease in the postprandial respiratory quotient 30 min and 60 min after breakfast on day 3 in the early dinner group compared with the late dinner group.
"Our findings show that despite the difference of only 3 hours, early dinner compared to late dinner resulted in a greater iAUC for blood glucose levels after dinner, higher average blood glucose levels the following day, and higher average blood glucose levels from evening to early morning (18:00 to 6:00)," wrote the authors. "There was no difference in respiratory quotient before breakfast between the groups, but the early dinner group exhibited a lower respiratory quotient after breakfast and increased lipid oxidation compared with the late dinner group."
The study titled, "Eating Dinner Early Improves 24-h Blood Glucose Levels and Boosts Lipid Metabolism after Breakfast the Next Day: A Randomized Cross-Over Trial," is published in the journal Nutrients.