Evaluation of Nutri-Score and NewTools-score in a Norwegian setting using a reference standard based on nutrition experts' ranking of foods' healthiness.

Background: The Nutri-Score is a color-coded front-of-pack nutrition label that classifies foods and beverages from A (higher nutritional quality) to E (lower nutritional quality). The NewTools-score is an adaptation of the Nutri-Score 2023-version, modified to better align with the Nordic Nutrition Recommendations. Validating nutrient profiling models in different countries is crucial for their reliability and effectiveness in promoting healthier food choices and combating non-communicable diseases. Objective: This study aimed to assess the convergent validity of the Nutri-Score and the NewTools-score by evaluating their agreement with a reference standard based on rankings of foods' healthiness by Norwegian nutrition experts. Additionally, we examined the consistency among these experts in rating foods' healthiness representative of the Norwegian diet. Design: Between August and December 2023, 29 nutrition experts completed a web-based questionnaire, scoring 100 foods on a scale from 1 (less healthy) to 6 (very healthy) based on the Norwegian food-based dietary guidelines. Agreement among experts was evaluated using descriptive statistics and Cronbach's alpha. We calculated both Nutri-Score and NewTools-score for all 100 foods and assessed their agreement with the reference standard through cross-classification and score distribution analyses. Results: The nutrition experts exhibited high agreement in their healthiness ratings of foods representative of the Norwegian diet. The Nutri-Score 2023-version showed good agreement with the experts for most foods, although discrepancies were observed for wholegrain and refined grains, fat content in dairy products, certain fish products, and plant-based dairy and meat substitutes. The NewTools-score displayed overall better agreement with the reference standard for several foods and with fewer discrepancies. Conclusions: Norwegian nutrition experts showed high agreement in rating the healthiness of foods representative of the Norwegian diet. While the Nutri-Score 2023-version aligned well with experts' ratings, the NewTools-score demonstrated better agreement than Nutri-Score in this Norwegian context, despite some remaining discrepancies.