Rapid Assessment of Reward-Related Eating: The RED-X5

OBJECTIVE: Obesity’s prevalence has created a plethora of questionnaires characterizing psychological aspects of eating behaviour, such as reward-related eating (RRE). The Reward- based Eating Drive questionnaires (RED-9, RED-13) broadly and deeply assesses the RRE construct. However, large-sample research designs require shorter questionnaires that capture RRE quickly and precisely. We sought to develop a brief, reliable, and valid version of the RED questionnaire. METHODS: We used all-subset correlation to find a subset that maximally associated with the full RED-13 in two separate samples. We validated results in a third independent sample. We also assessed internal consistency, test-retest reliability, and ability to explain variance in external outcomes. RESULTS: A 5-item questionnaire (RED-X5) correlated strongly with RED-13 in the independent sample (r = .95). RED-X5 demonstrated high internal consistency (omega total > .80) and 6- month test-retest reliability (r = .72). RED-X5 accurately reproduced known associations between RED-13 and body mass index, diabetes status, and craving for sweet and savory foods. As a novel finding, RED questionnaires predicted laboratory intake of chips. CONCLUSIONS: The RED-X5 is a short, reliable, and valid measure of the RRE construct and can be readily implemented in large-sample research designs where questionnaire space is limited. Materials are available at https://osf.io/bd3mg/.