The use of continuous subcutaneous insulin infusion (CSII) in young children is increasing in many countries, and is in Sweden currently 60% in preschool children. 1 An international consensus group has recommended CSII in the young age group. 2 The bolus calculator in the pump gives the individual the opportunity to use features that simplify the calculation of bolus doses, correcting for the current glucose level. Although a meta-analysis from 2013 found limited evidence for the use of carbohydrate counting in adults, 3 recent pediatric studies have found possible beneficial effects in decreasing HbA1c, both with CSII 4,5 and multiple daily injections (MDI), 6 and increasing the percentage of postmeal glucose readings within target. 7 Furthermore, learning about carbohydrates and carbohydrate counting can also result in overall increased knowledge regarding other components of the diet, which can lead to other benefits. The pharmacodynamic effect of 0.2 U/kg of subcutaneously injected insulin aspart was found to last approximately 4 hours in pubertal and 5 hours in prepubertal children in 1 study, 8 and similar results were found in another study using 0.15 U/kg. 9 If anything, these clamp studies lengthen the duration of insulin action, since the patient is resting in a bed, and the given dose will often have supplied both the basal 1348D STXXX10.