To support the“Weight Management Year”initiative and identify more effective promotional pathways，this study adopted a 2（information presentation format：video vs. text）× 2（information delivery format： narrative vs. non-narrative）between-subjects experimental design，with 503 participants. Using a pretest-posttest experimental approach，it explored the role of narrative transportation in shaping individuals’perceived social norms and behavioral intentions regarding low - sugar dietary behaviors. The results revealed a significant main effect of narrative transportation，along with a significant interaction between the format of information delivery and presentation. Mediating effect analysis showed that identification played a partial mediating role in the effects of both narrative videos and narrative texts on behavioral intentions. Identification and perceived social norms collaboratively constitute a chain mediating effect；identification can indirectly enhance the promotional effect of narrative information（in the form of videos or texts）on behavioral intentions to adopt low-sugar diets by strengthening individuals’perceived social norms. These findings suggest that narrative - based videos or articles can enhance individuals’sense of identification，reinforce their perceived social norms，and thereby increase their behavioral intentions.