10 T1DM patients on insulin pump therapy and subcutaneous continuous glucose monitoring (CGM) will be recruited. The study protocol is identical to protocol 1 with the following exceptions: 1. in 5 T1DM patients study 2 and study 3 will be two repeated 320 kcal meals; 2. in 5 T1DM patients study 2 and study 3 will be two repeated 640 kcal meals. The phenotypic results will be layered as in protocol 1 for reproducibility analysis.