Association of front-of-package warning label perceptions with Mediterranean diet adherence after bariatric surgery

Background: Front-of-package (FOP) warning labels are intended to support healthier food choices; however, evidence on how patients perceive these warnings after bariatric surgery and how such perceptions relate to dietary quality is limited. We examined the association between perceptions of FOP warning labels and Mediterranean diet (MedDiet) adherence among adults after bariatric surgery in Lima, Peru. Methods: This was an observational, analytical, cross-sectional study of 200 adults (18-59 years) attending postoperative follow-up at a private clinic in Lima, Peru. MedDiet adherence was assessed using the KIDMED index (originally developed for children/adolescents and used here as a proxy measure of MedDiet-aligned behaviors), and perceptions/understanding of FOP octagonal warnings were measured using a previously validated Peruvian questionnaire. Associations were evaluated using bivariate analyses and multivariable logistic regression, reporting adjusted odds ratios (aOR) and 95% confidence intervals (CI). Results: In adjusted models, higher self-reported preference for salty foods (aOR = 0.261; 95% CI: 0.136-0.501) and sweet foods (aOR = 0.490; 95% CI: 0.263-0.913) were associated with lower odds of medium/high MedDiet adherence. Greater agreement with the statement "I would follow the octagons, but nobody guides me on how to use them" was associated with higher odds of medium/high MedDiet adherence (aOR = 1.289; 95% CI: 1.002-1.659). Conclusion: Among adults after bariatric surgery, taste-preference indicators and perceptions regarding FOP warning labels were independently associated with MedDiet adherence. Given the cross-sectional design, these findings should be interpreted as associations rather than causal relationships and highlight the need to strengthen label literacy during postoperative nutrition education.