Despite the fact that awareness of eating disorders (EDs) has grown during the past decades, the conceptualisation, psychopathological characterisation and clinical diagnosis of EDs has proven to be problematic for both researchers and clinicians. Presently, diagnostic criteria employed for anorexia nervosa (AN) and bulimia nervosa (BN) are unable to account for an exceedingly high number of individuals with clinically significant eating symptoms or to properly address new clinical prototypes of ED. The aim of this paper is to describe the developments and current limitations of EDs diagnoses, and to recapitulate the recent literature on emerging phenotypes. Descriptions of the symptoms and behaviours of ED patients with diabulimia, orthorexia, muscle dysmorphia, drunkorexia and nocturnal eating disorders are featured with special focus on psychopathological classification and diagnostic ambiguity issues. An overview of non-specific eating and feeding disorders (EDNOS) in the newly released DSM-5 eating and feeding disorders section is also provided. Given the frequent transition between different phenotypes in patients with EDs and the common occurrence of individuals with clinically significant eating symptoms who evade diagnostic criteria, a better understanding and categorization of emerging EDs is required to guide psychiatric research and improve clinical outcomes.