Development and validation of a food literacy self-perceived assessment scale for the Portuguese adult population

Food literacy refers to the ability to access, process, and understand food-related information and apply this knowledge to make informed food choices in different contexts. In Portugal, there are no published data on food literacy levels at the population level using a measurement scale adapted to the national context, based on the principles advocated by the Mediterranean Food Wheel, and on the matrix Domains of Food Literacy (Planning, Management, Selection, Preparation, and Consumption) and Information Processing Skills (Assessing, Understanding, Evaluating, and Applying food system information). This study aimed to develop and validate a self-perceived food literacy assessment scale for Portuguese adults. The development process involved three phases: (1) content development based on previous scales and frameworks, (2) face validity evaluation by a panel of experts, and (3) a cross-sectional study performed with 252 participants via an online questionnaire. Principal component analysis (PCA) was used to assess content validity, and Cronbach’s alpha was used to measure internal consistency. Construct validity was tested by analyzing associations between food literacy and demographic, professional, and knowledge-related variables. The final Food Literacy Self-Perceived Assessment Scale included 42 items organized into a general index and five sub-indices (Planning, Management, Selection, Preparation, and Consumption). The scale showed good internal consistency (α ≥ 0.85). Higher food literacy scores were associated with being female, younger age (≤40 years), having a comfortable household income, working in nutrition-related fields, and possessing prior food-related knowledge. The validated Portuguese Food Literacy Self-Perceived Assessment Scale provides a useful tool for health professionals to assess food literacy among Portuguese adults.