Validation of REFRESH: A Dietary Screener for Rapid Evaluation FoR Environmentally Sustainable and Healthy Diets

The urgency of promoting sustainable diets, coupled with limited knowledge of dietary sustainability among health professionals, highlights the need for simple tools to assist in advocating for such diets in clinical settings.

We aimed to design a dietary screener to assess dietary healthiness and environmental sustainability, and validate it.

Rapid Evaluation FoR Environmentally Sustainable and Healthy diets (REFRESH) is a dichotomous tool targeting 10 key food groups for healthy diets with low environmental impacts. Each food group is scored as either 0 or 1 point, resulting in a total score ranging from 0 to 10-where 0 indicates the lowest and 10 the highest adherence to an environmentally sustainable and healthy diet. Internal consistency was assessed using the Kuder Richardson-20 (KR-20) coefficient. REFRESH's relative validity was compared against food diaries, evaluating item agreement, and using Bland-Altman analysis for the total REFRESH score. Cross-classification was tested in low, medium, and high adherence to sustainable healthy diets, along with weighted kappa index. Construct validity was evaluated through Pearson correlation between REFRESH-derived scores and health-promoting and detrimental food groups and nutrients, and environmental impact indicators, as derived from food diaries.

REFRESH had a KR-20 coefficient of 0.70, indicating good internal consistency. It showed high agreement with food diaries (60%-88% item agreement), and Bland-Altman analysis indicated that mean REFRESH scores were 1.1 points higher than food diaries. Cross-classification showed 59% agreement between methods, with only 1% of participants misclassified in the opposite category. REFRESH-derived scores positively correlated with health-promoting food groups and nutrients, and negatively with detrimental ones. Higher scores were linked to reduced environmental impacts.

REFRESH has demonstrated good validity for assessing dietary healthiness and environmental sustainability, helping identify individuals with suboptimal diets. REFRESH can be downloaded from https://osf.io/avby9/.