Galvanizing political commitment in the UN Decade of Action for Nutrition: Assessing commitment in member-countries of the Scaling Up Nutrition (SUN) Movement

•This study aims to measure political commitment for nutrition in SUN countries.•Early SUN joiners have higher expressed, institutional and operational commitment.•There is a strong, positive relationship between institutional and operational commitment.•High operational and embedded commitment associates with lower child stunting and women’s anaemia.•System-wide political commitment is important for achieving nutrition impact.