Adherence to the Mediterranean diet and changes in body mass index.

Background: Diet is considered a determinant of weight status, however, more evidence is needed for children. The Mediterranean diet (MedDiet) is one of the healthiest worldwide. This study analyzes the prospective association between adherence to the MedDiet at baseline and changes in standardized body mass index (zBMI) and the incidence of excessive weight.

Methods: 1389 children participated with a follow-up of 15 months. Weight, height, and adherence to the MedDiet were measured (baseline and follow-up).

Results: Multiple logistic regression analysis revealed that a high increase in zBMI was associated with lower odds of eating vegetables once [OR 0.74 (95% CI 0.57-0.98)] or more a day [OR 0.68 (95% CI 0.49-0.95)], nuts 2-3 times/week [OR 0.74 (95% CI 0.56-0.97)] or 2 cups of yogurt or/and cheese daily [OR 0.74 (95% CI 0.55-0.99)]. Not consuming each food item was used as reference. Multiple linear regression analysis showed a negative (β = -0.010, p = 0.040) association between the MedDiet at baseline and changes in zBMI at follow-up, significance disappeared (p = 0.082) after final adjustment for baseline zBMI.

Conclusion: Baseline MedDiet was not significantly associated with the incidence of excessive weight at follow-up. The MedDiet was positively associated with changes in zBMI, however the effect size was small.

Impact: The present longitudinal study contributes knowledge regarding the adherence to Mediterranean diet as a predictive variable of weight status evolution in children. Higher adherence to the Mediterranean diet at baseline was prospectively and inversely associated with changes in zBMI after 15 months of follow-up. Consuming vegetables, nuts, and yoghurt/cheese according to the recommendations reduces the likelihood of having a high increase in zBMI after 15 months of follow-up.