Fast-Acting Insulin Aspart and Insulin Pump Settings

Inclusion Criteria: * Type 1 diabetes for ≥ 5 years * HbA1c 53-75 mmol/mol (7.0-9.0%) * Insulin pump treatment for ≥ 6 months (all insulin pump makes except hybrid closed-loop systems are eligible for inclusion) * CGM use for ≥ 6 months (all CGM makes are eligible for inclusion) * Carbohydrate counting for all snacks and meals * Use of the insulin pump bolus calculator for all meals and snacks Exclusion Criteria: * Breast-feeding, pregnant, planning to become pregnant or of child-bearing potential and not using adequate contraceptive methods * Gastroparesis (clinical assessment) * Shift work * Changing insulin needs throughout the menstrual cycle that requires different basal rate patterns * Use of a hybrid closed-loop system * Use of flash glucose monitoring * Use of anti-diabetic medicine (other than insulin), corticosteroids or other drugs affecting glucose metabolism during the study period or within 30 days prior to study start * Chronic paracetamol use * Alcohol or drug abuse * Severe cardiac disease or retinopathy contraindicating HbA1c below 53 mmol/mol * Impaired renal function (eGFR\< 60 ml/min/1.73 m2) * History of local skin reactions to Fiasp and/or Iasp * Other concomitant medical or psychological condition that according to the investigator's assessment makes the patient unsuitable for study participation * Lack of compliance with key study procedures at the discretion of the investigator * Unacceptable adverse events at the discretion of the investigator * Less than 40 weeks guarantee remaining on insulin pump