This study aims to adapt and validate the Sustainable HEalthy Diet (SHED) Index for the Portuguese adult population, which was developed to assess sustainable and healthy eating patterns. Data were collected using a web-based questionnaire administered through interviews with 347 individuals aged between 18 and 65 years old. The SHED Index evaluates 30 items, allowing for the assessment and scoring of sustainable and healthy eating patterns. The higher the SHED Index score, the more sustainable and healthier the diet. A semi-quantitative food frequency questionnaire was used to assess the participants' dietary intake. The criterion validity was examined by testing the relationship between the SHED Index score and adherence to the Mediterranean Diet. Reproducibility was assessed by determining agreement and reliability with test-retest. Construct validity was confirmed based on established criteria. A higher SHED Index score was associated with moderate to high adherence to the Mediterranean diet, while it was inversely related to the proportion of animal-sourced foods in the overall food intake (r = -0.281, p < 0.001). Good reliability and agreement were found for the SHED Index score. Our findings suggest that the SHED Index is a valid and reliable tool for assessing sustainable and healthy diets in the Portuguese adult population.
Keywords: diet indexes; food sustainability; healthy eating; sustainable nutrition; validity.