The inventors have produced two high specificity and high affinity monoclonal antibodies that bind to human neuromedin U (NMU). Methods and compositions are provided for treating an individual in need thereof (e.g., an individual who is obese and/or has diabetes) by administering an anti-NMU/NMUR agent (e.g., an anti-NMU antibody). For example, methods and compositions are provided for increasing circulating insulin in an individual. Methods and compositions are also provided for detecting neuromedin U (NMU) (e.g., in a biological sample such as serum). Methods and compositions are also provided for predicting whether an individual will develop diabetes and/or PDAC, and for identifying an individual who would benefit from administration of an anti-NMU/NMUR agent.