Diet is the first line and the main therapeutic strategy in the treatment of gestational diabetes (GDM) with the primary objective to achieve normal blood glucose levels while promoting adequate maternal weight gain and fetal growth. In the L diet, glycemic index and fiber content were <=50 and >=35 g daily, respectively, while in the M diet they were >50 and <35 g daily. Only four patients (1 in the L diet group, 3 in M diet group) have disregarded the nutritional prescription thus necessitating insulin therapy. [Extracted from the article]