Background and Aims: Medical nutrition therapy plays a major role in the management of gestational diabetes mellitus (GDM). However, control of postprandial blood glucose values is often a challenge in Asian Indian GDM women due to high carbohydrate content in Indian diet. Materials and Methods: Women presenting with GDM diagnosis were randomised to high fiber complex carbohydrate diet and soya based protein rich diet (25% of cereal part in the high fiber, complex carbohydrate diet replaced by soya food) groups. Results: At the end of one week after initiation of dietary intervention, patients who received high fiber complex carbohydrate diet (n=30) had significantly higher postprandial blood glucose levels than those who received soya based protein rich diet (n=32). The need for insulin therapy at the end of one week after initiation of dietary intervention (15.62% vs. 40.0%) and at delivery (18.75% vs. 50%) were significantly lower in soya based protein rich diet group. Maternal thyroid function at diagnosis of GDM and delivery and neonatal TSH were not significantly different between the groups. Conclusion: Consumption of soya based protein rich diet reduced the need for insulin therapy in subjects with GDM. Short term consumption of soya food did not alter maternal and neonatal thyroid functions.