Although excessive intake of sodium is known to cause various diseases and threaten public health and policies for reducing overconsumption of sodium are being implemented, the theoretical research on sodium intake is incomplete. This study attempted to provide a policy basis by examining whether or not planned behavior theory, which is a typical health communication theory used to describe health-related behaviors, can be applied to explain sodium intake behavior. Especially, sodium ingestion behaviors were compared using the theory of actions planned for men and women as well as young people, middle-aged, and elderly persons, who are predicted to show differences in eating habits. In this study, questionnaires were prepared to measure the daily eating habits of subjects and subordinate factors of planned behavior theory: behavioral beliefs, outcome expectations, normative beliefs, compliance motivation, and control beliefs. Questionnaires were given to 93 college students and their families. As a result of the difference analysis and path analysis of the questionnaire responses, the following suggestions were obtained. First, age difference is more obvious than sex difference in terms of low salt intentions. For example, older people are healthier than younger people in terms of eating habits and health concerns. Second, the elderly are more likely to practice the low-salt formula when they are provided information on the benefits and effects of the low-salt formula compared to younger ones. Third, systematic efforts are needed to promote a culture that emphasizes the health benefits of a low salt diet rather than providing piecemeal information on the advantages and effects of a low salt diet.