Nutrition literacy and food literacy have become increasingly important concepts in health promotion. Researchers use one or the other term to describe the competencies needed to maintain a healthy diet. This systematic review examines whether these terms are synonymous or if their meanings are substantially different.We searched major bibliographic databases (Web of Science, PubMed, ScienceDirect, CINAHL, SocIndex and ERIC) for publications that provided an original definition of nutrition or food literacy. Then we used Nutbeam's tripartite health literacy model as an analytical grid. The definitions we found included specific competencies, which we mapped to the domains of functional, interactive, or critical literacy.In the 173 full-text publications we screened, we found six original definitions of nutrition literacy, and 13 original definitions of food literacy. Seven food literacy definitions were integrated into a conceptual framework. Analysing their structure revealed that nutrition literacy and food literacy are seen as specific forms of health literacy, and represent distinct but complementary concepts. Definitions of nutrition literacy mainly described the abilities necessary to obtain and understand nutrition information. Definitions of food literacy incorporated a broader spectrum of theoretical and practical knowledge and skills. To be food literate also means to apply information on food choices and critically reflect on the effect of food choice on personal health and on society. Since food literacy is based on a more comprehensive understanding of health behaviours, it is the more viable term to use in health promotion interventions. For the practical implication, a harmonization of the different definitions is desirable.