Adherence to the Mediterranean diet and changes in body mass index in Spanish children

Background Unhealthy diets are a major driver of childhood obesity. On the other hand, the Mediterranean diet is considered one of the healthiest diets worldwide. Therefore, the objective of the present study was to analyze the prospective association between adherence to the Mediterranean diet at baseline and changes in standardized body mass index (zBMI) in children and the incidence of excessive weight in Spanish children.Methods This community-based cohort study was carried out between 2012 and 2014 with a mean follow-up of 15 months and included 1389 children from 8 to 10 years old. Weight and height were measured at baseline and follow-up. Adherence to the Mediterranean was determined by the KidMed index.Results Multiple logistic regression analysis revealed that a high increase in zBMI (5th quintile of change) was associated with lower odds of having vegetables once [OR 0.74 (95% CI 0.57–0.98)] or more than once a day [OR 0.68 (95% CI 0.49–0.95)], having nuts 2-3times/week [OR 0.74 (95% CI 0.56–0.97)] or 2 cups of yoghurts or/and cheese daily [OR 0.74 (95% CI 0.55–0.99)]. Multiple linear regression analysis showed a negative (β=-0.010, p = 0.040) association between adherence to the Mediterranean diet at baseline and changes in zBMI at follow-up, although the statistical significance disappeared (p = 0.082) after final adjustment for baseline zBMI. Conclusions: Baseline adherence to the Mediterranean diet was not significantly associated with the incidence of excessive weight (overweight and obesity) at follow-up. Adherence to the Mediterranean diet was favorably associated with changes in zBMI in Spanish children, however the effect size was small.