Appetite rumination refers to repetitive, intrusive thoughts about appealing foods that may contribute to dysregulated eating. Existing measures of eating‑related cognition often fail to capture such spontaneous, cue‑triggered food intrusions, underscoring the need for a construct that reflects everyday ruminative thinking about food. Building on the original Hunger Rumination Scale, this study aimed to validate the hierarchical structure of appetite rumination and examine its role within a cognitive–emotional framework involving mindfulness, impulsivity, and emotional eating. A web-based survey was conducted among 300 Japanese adults. Confirmatory factor analyses were used to test three competing models of the Appetite Rumination Scale (ARS): a correlated three-factor model, a second-order factor model, and a single-factor model. Both the correlated and second-order models demonstrated an excellent fit, whereas the single-factor model showed a poorer fit, supporting a hierarchical structure comprising ordinary food-triggered rumination, emotion-driven appetite rumination, and special food-triggered rumination. Structural equation modeling with participants with body mass index (BMI) ≥ 18.5 (n = 252) revealed that lower mindfulness predicted higher impulsivity, which, in turn, increased appetite rumination and emotional eating. Appetite rumination was strongly and positively associated with emotional eating, highlighting its important role in maladaptive eating tendencies. Psychological variables were only weakly related to BMI. These findings provide robust evidence for the factorial and construct validity of the ARS and position appetite rumination as the key cognitive mechanism linking mindfulness, impulsivity, and emotional eating. The ARS offers a psychometrically sound tool for future research and may inform interventions targeting repetitive food-related thinking.