Background/Aims: Shift-workers often eat at night when the body is primed for sleep, which may have implications for health. This study examined the impact of consuming a large versus small snack at night on glucose response to breakfast.
Methods: 29 healthy subjects (21-35y; 18F) participated in a simulated nightshift laboratory study including one baseline sleep (BL; 22:00h-07:00h) and one night awake with allocation to a large snack (2100kJ; 18g total fat, 20g protein, 63g carbohydrate) or small snack (840kJ; 6g total fat, 7g protein, 31g carbohydrate) using a parallel study design. Snacks were consumed between 00:00h-00:30h. A mixed meal breakfast (2100kJ) was consumed at 08:30h the following morning. Interstitial glucose was measured continuously using Medtronic Glucose Monitors and was averaged into 5-minute bins. Area under the curve (AUC) for 90-minutes post-breakfast was compared following sleeping at night and a night awake for each snack group.
Results: Pre-breakfast, glucose levels did not significantly differ between BL and post-nightshift (p>0.05), nor did they differ between snack groups (p>0.05). A snack group*day interaction was found (F(1,17)5.36, p=0.03) such that in the large snack group, AUC response to breakfast was significantly higher post-nightshift (+17.8±6.7%) compared to BL (p=0.003). AUC did not significantly differ (p>0.05) between days in the small snack group.
Conclusions: Compared to a small snack, consumption of a large snack at 00:00h impaired the glucose response to breakfast for up to 90-minutes. Further research into optimal quantity and content of snacks will inform dietary recommendations for shift workers.