Mean HbA1c over 4 years after reduction of carbohydrates in all and in subgroups with different degrees of adherence. The amount of carbohydrates was 75 g/day or less according to the person’s own preferences. Mainly, starchy food was reduced. The insulin doses were adapted accordingly. §N number of patients in groups. A = all patients (100%). B = non adherent (52%). C = partly adherent with intra-person variations over time. D = excellent adherence (27%). C + D (47%).