To provide the minimal impact of the previous breakfast, all patients will receive up to 120 kcal of carbohydrates and <100 kcal from protein and fat for the first breakfast (without any extended bolus) Patients receive a standardized pure protein meal at a second breakfast time. Meal insulin will be given as a square bolus or no meal -insulin will be given at all. The 5h post-meal glucose excursions will be recorded by self-blood glucose measurements (SMBG) (every 30 minutes) and continuous glucose monitoring system (CGMS). The intervention is taking part under in-patient clinical conditions.