Introduction: Food insecurity is a critical barrier to following dietary advice during pregnancy, particularly for women with or at risk of gestational diabetes mellitus (GDM). Poor access to nutritious food contributes to excess gestational weight gain and adverse maternal and neonatal outcomes. This trial aims to evaluate the impact of a food-based intervention—'Produce Prescription’—on gestational weight gain in food-insecure pregnant women, integrating nutrition access into antenatal care as a form of social prescribing. Method: A randomised controlled trial will recruit 316 pregnant women (<20 weeks gestation) from Sydney hospitals. Eligible participants will have food insecurity, overweight/obesity, and either diagnosed GDM or high GDM risk. Women in the intervention group will receive weekly home deliveries of fresh produce, wholegrains, and nuts/seeds, plus three telehealth dietetic sessions to support dietary improvement. The control group will receive standard antenatal care. Assessments occur at baseline, midpoint (24–28 weeks), pre-delivery (34–38 weeks), and post-delivery. The primary outcome is change in gestational weight gain from baseline to pre-delivery. With 80% power, the study can detect a ≥2.2 kg difference between groups. Secondary outcomes include maternal (GDM, hypertension, excess weight gain, caesarean section) and neonatal (preterm birth, large-for-gestational age, perinatal mortality) risks. Findings are pending. Discussion: We are currently recruiting for this world-first trial to use a produce delivery model for pregnant women with or at high risk of GDM. Embedding food access within antenatal care could offer a scalable, non-pharmaceutical approach to improve pregnancy outcomes. A process evaluation and economic analysis will inform feasibility for integration into social prescribing pathways and healthcare policy. If successful, the model may serve as a practical intervention for addressing food insecurity during pregnancy.