Developing and Validating an Instrument to Evaluate Theory-Based Behavioral Antecedents of Consuming a High-Fiber Diet

Obesity is a major public health concern, with low consumption of fiber-rich foods (e.g., fruits and vegetables) commonly cited as a causal factor. The purpose of this study was to evaluate the validity of a survey measuring the constructs of the Reasoned Action Approach under the context of consuming a high-fiber diet. After an initial draft of the survey was developed, it was evaluated by a panel of six experts to establish face and content validity. Next, data were collected from an adult sample (n = 878), and psychometric data revealed indices of reliability (Cronbach’s alpha) and validity (confirmatory factor analysis). The average age of adults was 51.5 years (±12.8), and a majority were Caucasian (81%), and women (93%). With regards to construct validity, the model structure had adequate fit (e.g., Comparative Fit Index = 0.960). In addition all items loaded significantly on its corresponding scale. For internal consistency reliability, all Cronbach’s alpha scores were > 0.70. Overall the survey appears to be a promising tool for researchers and practitioners. Understanding the theoretical determinants of fiber consumption will help tie theory together with practice.