OBJECTIVE: To evaluate the identification and objective understanding of precautionary legends regarding non-sugar sweeteners (NSS) and caffeine in sweetened beverages (SBs). MATERIALS AND METHODS: The labeling questionnaire from the National Health and Nutrition Survey 2021 was administered to Mexican adults over 20 years old. Identification was assessed when the participants reported seeing the legend. Objective understanding was determined by correctly evaluating the nutritional quality of SBs. For this evaluation, 50% of the participants were presented with an image of a sugary drink displaying the precautionary legend, while the other 50% without the legend. RESULTS: For the NSS legend, the odds of correctly evaluating the nutritional quality of a SB were higher among participants who identified the NSS legend (OR: 1.62, 95%CI: 1.12,2.34) compared to those who did not. Similarly, the odds were higher when the product was presented with the legend compared to when it was not (OR: 1.23, 95%CI: 1.01,1.51). For the caffeine legend, the odds of correctly evaluating the nutritional quality of a SB were four times higher among participants who identified the legend compared to those who did not (OR: 3.97, 95%CI: 1.98,7.97). CONCLUSION: Greater effectiveness was observed among participants who identified the legends. We recommend implementing strategies to enhance the identification of precautionary legends.