Promoting a traditional Mexican diet (TMexD) could potentially reduce high rates of non-communicable diseases (NCD) and support food sustainability in Mexico. This study aimed to develop an index to assess adherence to the TMexD.

A three-round Delphi study was conducted to examine the food groups, specific foods and food-related habits that would constitute a TMexD index. Participants selected the TMexD items using Likert scales, lists of responses, and yes/no questions. Consensus was determined using percentages of agreement, mean values and/or coefficients of variation.

Online Delphi study.

Seventeen nutrition and food experts in Mexico completed all three rounds.

The resulting index (ranging from 0 to 21 points) consisted of 15 food groups, containing 102 individual foods. Food groups included in higher quantities were maize, other grains, legumes, vegetables, fruits, herbs, nuts and seeds, and tubers. Animal foods, vegetable fats and oils, homemade beverages, maize-based dishes, and plain water were also included, but in lower quantities. The food-related habits included were consuming homemade meals, socialising at meals and buying food in local markets. Consensus was reached for all index items apart from quantities of consumption of six food groups (herbs, nuts, grains, tubers, dairy and eggs).

Although future research could improve the measures for which consensus was not reached, the TMexD index proposed in this study potentially displays a healthy and sustainable dietary pattern and could be used to examine links between the TMexD and health outcomes in Mexican populations.