The double burden of malnutrition—the simultaneous manifestation of both undernutrition and overweight and obesity—continues to be a major worldwide public health problem. Having updated data on key malnutrition outcomes is crucial for evidence-based actions to effectively address one of the primary contributors to poor health globally. In The Lancet, the NCD Risk Factor Collaboration (NCD-RisC) present a worldwide, up-to-date, and large body of evidence on key malnutrition components: underweight or thinness and obesity. Using extensive high-standard population-based data, the authors estimate the age-standardised prevalence of underweight or thinness and obesity and the combined burden for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years) in 200 countries and territories over the past three decades (1990–2022). This study has some limitations, including scarce data availability for some countries and absent data for three, scarce data for the youngest and oldest age groups, potential bias due to non-response in health surveys and possible model mis-specification related to data variability, and an absence of reporting on height (an important nutrition indicator), among others. Nevertheless, the authors build a comprehensive picture of the worldwide dynamics of underweight or thinness and obesity.