Adherence to the EAT-Lancet index is associated with lower diet costs in the Mexican population

Background Poor diet quality contributes to morbidity and mortality and affects environmental sustainability. The EAT-Lancet reference diet offers a healthy and sustainable solution. This study aimed to estimate the association between diet cost and dietary quality, measured with an EAT-Lancet Index. Methods An EAT-Lancet index was adapted to assess adherence to this dietary pattern from 24-h recalls data from the 2012 and 2016 Mexican National Health and Nutrition Surveys (n = 14,242). Prices were obtained from the Consumer Price Index. We dichotomized cost at the median (into low- and high-cost) and compared the EAT-Lancet index scores. We also used multivariate linear regression models to explore the association between diet cost and diet quality. Results Individuals consuming a low-cost diet had a higher EAT-Lancet score than those consuming a high-cost diet (20.3 vs. 19.4 from a possible scale of 0 to 42; p < 0.001) due to a lower intake of beef and lamb, pork, poultry, dairy, and added sugars. We found that for each one-point increase in the EAT-Lancet score, there was an average decrease of MXN$0.4 in the diet cost (p < 0.001). This association was only significant among low- and middle-SES individuals. Conclusions Contrary to evidence from high-income countries, this study shows that in Mexico, adhering to the EAT-Lancet reference diet is associated with lower dietar costs, particularly in lower SES groups. These findings suggest the potential for broader implementation of healthier diets without increasing the financial burden.