Author(s): LIU, H., CHEN, Y., Institution: NATIONAL TAIWAN NORMAL UNIVERSITY, Country: TAIWAN, Abstract-ID: 1107

INTRODUCTION:
Meal timing is an important factor influencing metabolic health, with late eating potentially disrupting circadian rhythms. As dinner is typically the meal with the highest energy intake, it remains unclear whether the timing of dinner consumption affects lifestyle patterns (such as physical activity and sleep) and dietary behaviours and whether it further influences glycaemic responses outside of laboratory settings.
METHODS:
In this randomized crossover study, 14 healthy adults (mean ± SD; age: 26.3 ± 5.3 years; BMI: 22.0 ± 2.0 kg/m²) conducted 7 days of early dinner (ED, 17:30–19:00) and late dinner (LD, 20:30–22:00) consumption in a free-living environment. Participants were required to consume a minimum dinner energy intake based on preliminary monitoring. Physical activity was measured with wGT3X-BT. Sleep was assessed using the MotionWatch 8. Glucose levels were tracked using continuous glucose monitoring FreeStyle Libre 2. A paired sample t-test was utilized to compare the abovementioned results between trials.
RESULTS:
There were no differences on energy intake (759 ± 167 vs. 794 ± 198 kcal, p = 0.381) between trials. In terms of physical activity, sedentary behaviours (81.7 ± 4.7 vs. 82.4 ± 5.8 %, p = 0.423), light-intensity (15.3 ± 3.3 vs. 14.7 ± 4.4 %, p = 0.430) and moderate-intensity (2.9 ± 2.2 vs. 2.8 ± 2.2 %, p = 0.736) physical activity did not differ between the ED and LD trials. There were no differences on time in bed (7.4 ± 0.5 vs. 7.4 ± 0.5 h, p = 0.983), total sleep duration (5.9 ± 0.8 vs. 5.7 ± 0.8 h, p = 0.224), sleep efficiency (77.2 ± 7.5 vs. 75.5 ± 8.0 %, p = 0.219) and sleep latency (15.3 ± 7.2 vs. 17.2 ± 14.2 min, p = 0.717) between ED and LD. The 7-day average (104 ± 6 vs. 103 ± 5 mg/dL, p = 0.926), hourly peak (111 ± 6 vs. 110 ± 6 mg/dL, p = 0.883) and nadir (99 ± 6 vs. 97 ± 5 mg/dL, p = 0.518) of glucose levels also showed no differences between ED and LD.
CONCLUSION:
Short-term early or late dinner intake may not acutely affect physical activity, sleep parameters and glucose responses under free-living conditions in healthy adults.