Randomised controlled trial on the effect of Chilean nutritional warning labels versus nutri-score in food purchasing intentions.

Abstract

The main factor causing obesity is the consumption of ultra-processed products. We aim to evaluate the effectiveness of a front-of-pack nutritional warning label system versus a simple nutritional traffic light for promoting the purchase of fresh foods and enhancing the nutritional profile of the household shopping basket. Randomised controlled intervention study of the weekly grocery shopping basket at a virtual supermarket of a sample of Spanish adults. Participants were randomised to the Chilean warning label (intervention group) or French Nutri-Score systems (control group). After making the simulated purchase, the participants completed a questionnaire on socio-demographic variables. To compare the food and nutritional profiles of the two groups, we used the independent samples t-test and multiple linear regression analysis. There were 747 participants, 391 allocated to the CWL group and 356 to the NS group. No differences were found in the percentage of fresh and minimally processed products or the nutritional profile among groups. Compared to the participants allocated to the Nutri-Score, the mean energy per 100 g of product in the shopping basket of those allocated to the warning system was 6.6 kcal lower (p = 0.05), and the mean protein content was 0,4 g lower (p = 0.04). In secondary adjusted analysis, the mean sugar content per 100 g of product in the participants allocated to the warning system was 0.63 g higher than that of those allocated to the Nutri-Score (p = 0.01), while the mean protein content was 0,44 g lower (p = 0.02). No differences were found in the percentage of fresh and minimally processed products or the nutritional profile in the weekly shopping basket of a sample of Spanish consumers. The protein content was slightly lower among participants allocated to food warning labels than in those allocated to the Nutri-Score system.