Worldwide, the demand for healthcare exceeds what individuals and governments are able to afford. Priority setting is therefore inevitable, and mental health services have often been given low priority in the decision-making process. Drawing on established economic criteria, and specifically the work of Philip Musgrove, key factors which influence government decision-making about health priorities are reviewed. These factors include the size of the health burden, the availability of cost-effective interventions to reduce the burden, whether private markets can provide the necessary treatment efficiently, whether there are "catastrophic costs" incurred in accessing treatment, whether negative externalities arise from not providing care, and if the "rule of rescue" applies. Beyond setting priorities for resource allocation, governments also become involved where there is a need for regulation to maintain quality in the delivery of healthcare. By providing field-specific examples for each factor, we illustrate how advocates in the eating disorder field may use evidence to inform government policy about resource allocation and regulation in support of individuals with an eating disorder.