Psychometric properties and predictive validity of Brazilian reward-based eating drive scale

This study aimed to adapt and validate the Reward-Based Eating Drive Scale (RED-13) for Brazilian Portuguese and assess its psychometric properties and predictive validity. The adaptation process followed established cross-cultural guidelines, including translation, synthesis, back-translation, expert committee review, and pilot testing. Content validity was evaluated using the Content Validity Index. A total of 452 adults aged 18-59 years, recruited online, participated in the psychometric assessment. Confirmatory factor analysis supported the scale's three-dimensional structure (RMSEA < 0.0001, SRMR = 0.041, TLI = 1.000, CFI = 1.000). Internal consistency was high (α = 0.921, ω = 0.922). RED-13 BR scores showed moderate correlations with food cravings and weak correlations with body mass index (rho = 0.266, <i>p</i> < 0.001). Receiver operating characteristic analysis indicated predictive ability for pre-obesity and obesity. These findings suggest that the RED-13 BR is a valid and reliable instrument for assessing reward-based eating behavior in Brazilian adults.