Development and validation of a comprehensive food literacy questionnaire for adolescents integrating knowledge, skills, and environmental influences

Food literacy refers to the individual’s capabilities to make informed food choices. While there are several conceptual frameworks for defining food literacy, food literacy questionnaires specifically designed for adolescents are scarce. This study aimed to develop and validate a comprehensive food literacy questionnaire for adolescents. The study consisted of three stages. First, a concept questionnaire was developed based on literature, expert sessions, and existing food literacy questionnaires. Secondly, a validation study was conducted among 673 Dutch secondary school adolescents aged 12–18 years. The questionnaire was evaluated and optimized based on the facility index, factor analyses, Cronbach’s alpha, and process evaluation questions. Thirdly, the optimized food literacy questionnaire was completed by 540 Dutch adolescents (grade 1–3) for further evaluation and validation. The concept questionnaire consisted of 63 items covering four main concepts: Knowledge, Skills, Social environment, and Physical environment. Based on the factor analyses results, the latter two concepts were reclassified into Self-control and Handling socio-cultural influences, which improved reliability. Based on the validation study results, ten knowledge questions (too easy or too difficult) and six statements were removed. This resulted in an optimized 47‑item questionnaire. The results from the third phase showed that this questionnaire was sufficiently reliable (Cronbach’s alpha between 0.72 and 0.83) and no longer contained knowledge questions that were too difficult or too easy. The questionnaire that was developed to assess adolescents’ food literacy contains a wide range of aspects related to being capable of making informed and conscious food choices. After testing in two validation studies, this questionnaire with 47 items was found to be sufficiently valid, reliable, and feasible to be administered in secondary schools. This food literacy questionnaire can be widely used in adolescent research and practice.