Behaviors associated with eating are often cited as one of many factors contributing to the development of childhood obesity. Behavior is thought to be guided, in part, by personal beliefs and tacit knowledge, which arise from the interpretation of sensory-motor experiences. Tacit knowledge, however, differs from declarative knowledge or the acquisition of factual information attained during formal education. Yet, there are no known publications that review children's and adolescent's tacit and declarative knowledge of eating. The purpose of this integrative review was to examine the evidence regarding children's and adolescents' knowledge of eating. Literature searches were conducted in CINAHL, PsycINFO, Web of Science, and Google Scholar. Selected publications included in the integrative review were empirical studies written in English that described children's and adolescent's knowledge of eating. A total of 548 publications resulted from the searches. Thirty met the inclusion criteria. Preschool-age children understood concepts related to edibleness, nutrition, and digestion as a result of their experiences with food and eating. School-age children and adolescents correctly identified not only facts about food, nutrition, and health, but also factors that influenced their decisions about eating. School-age children and adolescents also expressed concern about their diet, barriers to being healthy, and their appearance. Evidence presented in this integrative review revealed that children, including those of preschool-age, know a great deal about eating. Moreover, the evidence suggests that beliefs and tacit knowledge are more influential in directing eating behaviors than declarative knowledge or knowing facts about food, nutrition, the body, or health. Understanding what children believe and tacitly know about eating will be useful in tailoring interventions to prevent the development of childhood obesity.