Medical Nutrition Therapy with Meal Sequence and Divided Carbohydrate Intake: Associations with Ketonuria Resolution and Neonatal Outcomes in Gestational Diabetes Mellitus

Background/Objectives: Ketonuria is frequently observed in women with gestational diabetes mellitus (GDM), particularly when energy and carbohydrate intake is inadequate. This retrospective study evaluated nutritional status and neonatal outcomes following dietitian-led medical nutrition therapy (MNT) in 517 Japanese women with GDM with and without ketonuria. Methods: Dietary counseling emphasized a meal sequence in which vegetables were consumed before protein-rich foods and carbohydrates were consumed last, together with divided carbohydrate intake (4–5 meals/day), to attenuate postprandial glucose excursions while ensuring adequate energy and carbohydrate intake. Clinical characteristics, dietary intake, and neonatal outcomes were compared between women with and without ketonuria. Results: Among the participants, 143 (27.7%) exhibited ketonuria. The 60-min plasma glucose concentration during the OGTT was significantly higher in the ketonuria-positive group, whereas age, pre-pregnancy BMI, HbA1c, and glycated albumin did not differ between groups. Energy and carbohydrate intakes were significantly lower in the ketonuria-positive group before and after GDM diagnosis. Following GDM diagnosis, dietary intake decreased further in both groups; however, after MNT, energy and carbohydrate intakes increased significantly, and ketonuria resolved in all affected women. Birth weight, cesarean section rates, and the prevalence of congenital anomalies did not differ significantly between groups. None of the participants subsequently required insulin therapy during pregnancy. Conclusions: These findings suggest that dietitian-led MNT incorporating meal sequence and divided carbohydrate intake was associated with improved nutritional adequacy and resolution of ketonuria, with favorable neonatal outcomes observed in Japanese women with GDM regardless of urinary ketone status.