In this episode of Milestones in Maternal Nutrition, Professor Andrew Prentice speaks with Dr. Nandita Perumal about healthy weight management before and during pregnancy. Dr. Perumal explains how being underweight and overweight can impair fertility, while obesity increases the risk of complications including miscarriage, neural tube defects, gestational diabetes, hypertensive disorders, preterm birth and adverse neonatal outcomes. The discussion explores current recommendations for gestational weight gain, diet and physical activity, highlighting emerging evidence that weight gain targets may need to be individualized according to the degree of maternal obesity. Together, they examine the challenges of translating lifestyle interventions into practice and the importance of supporting healthy weight before conception to improve outcomes for both mothers and their children.