Protein-Containing Breakfasts Are Associated with Reduced Postprandial Glycaemic Excursions in Children and Young People with Type 1 Diabetes: A Pragmatic Study.

Background/Objectives: This study examined whether adding 10 g of protein to a high glycaemic index (GI) breakfast could attenuate postprandial glycaemic responses in children and young people (CYP) with type 1 diabetes (T1D). Postprandial glucose responses following this modified breakfast were compared with those after a high GI breakfast alone, a low GI breakfast, and participants' usual breakfast. Methods: A pragmatic randomised crossover study was conducted in n = 25 CYP aged 5-17 years. Participants consumed three standardised test breakfasts on two study occasions and their usual breakfast as a control. Test meals varied by GI, glycaemic load (GL), and protein content: high GI/high GL (HGL), high GI/high GL with an additional 10 g protein (HGLP), and low GI/medium GL (MGL). Continuous glucose monitoring data were collected for three hours following each meal. Linear mixed model analyses were used, and a subgroup analysis included participants using hybrid closed-loop (HCL) systems. Results: Participants' (mean age 12.1 ± 3.6 years) mean postprandial glucose over a three-hour follow-up was significantly lower following the HGLP meal compared with the HGL meal (8.0 ± 2.2 vs. 9.5 ± 2.5 mmol/L; p < 0.01). Time in Range (TIR) over 180 min was significantly shorter after the HGL meal compared with the control, HGLP, and MGL meals (p ≤ 0.03). Glucose excursions at 30 and 60 min were significantly higher following the HGL meal compared with all other meals, with differences persisting up to 120 min when compared with the HGLP meal. Results were not different for participants using HCL systems. Conclusions: Adding 10 g of protein to a high GI breakfast or choosing a lower GI option improves postprandial glycaemic control in CYP with type 1 diabetes.