Assessment of the alignment between Nutri-Score and the NOVA classification before and after the Nutri-Score algorithm update: analysis of 450 food products from the Polish retail market

Background Nutri-Score is one of the most widely used front-of-pack nutrition labelling (FOPNL) systems in Europe. Whereas Nutri-Score assesses nutritional quality, the NOVA classification categorises foods according to the extent and purpose of processing. An updated version of the algorithm was introduced to improve alignment with current dietary recommendations and reduce favourable ratings assigned to highly and ultra-processed foods. This study aimed to assess the alignment between Nutri-Score and the NOVA classification before and after the algorithm update, and to analyse changes in the classification of food products available on the Polish retail market. Methods A total of 450 food products available in Polish supermarkets and representing various food categories were analysed. Products were classified according to the Nutri-Score algorithm (before and after the 2023 update) and the NOVA classification system. A healthfulness classification based on Part B of the KomPAN questionnaire and supplementary author-defined criteria was used to assess changes in Nutri-Score ratings before and after the algorithm update across products with different healthfulness profiles. Results Agreement between Nutri-Score and the NOVA classification increased following the algorithm update (ρ = 0.571 after the update vs. ρ = 0.518 before the update). The proportion of Nutri-Score–NOVA classification conflicts decreased from 8.9% to 3.1% ( p < 0.001). At the same time, 68.7% of products retained the same letter grade after the algorithm update. Conclusions The updated Nutri-Score algorithm was associated with improved alignment with the NOVA classification and a reduction in the number of favourable ratings assigned to ultra-processed foods available on the Polish retail market.