The SHED Index: a tool for assessing a Sustainable HEalthy Diet

Purpose Promoting sustainable diets through sustainable food choices is essential for achieving the sustainable development goals set by the United Nations. Establishing a practical tool that can measure and score sustainable and healthy eating is highly important. Methods We established a 30-item questionnaire to evaluate sustainable-dietary consumption. Based on the literature and a multidisciplinary advisory panel, the questionnaire was computed by principal component analysis, yielding the Sustainable-HEalthy-Diet (SHED) Index. A rigorous multi-stage process included validation in training-verification sets, across recycling efforts, as an indicator of environmental commitment; and validation across the proportion of animal-protein consumption, as an indicator of adherence to a sustainable and healthy dietary-pattern. The EAT-Lancet reference-diet and the Mediterranean-Diet-score were used to investigate the construct validity of the SHED Index score. Reliability was assessed with a test–retest sample. Results Three-hundred-forty-eight men and women, aged 20–45 years, completed both the SHED Index questionnaire and a validated Food-Frequency-Questionnaire. Increased dietary animal-protein intake was associated with a lower SHED Index total score ( p