High monetary costs of dietary patterns associated with lower body mass index:: a population-based study

Introduction: Food choice is strongly influenced through economic constraints. The monetary costs for foods, especially those foods associated with a lower risk of obesity, have considerably increased during the last years. The purpose of this study was to determine the cost differences between low and high adherence to two dietary patterns which have been inversely associated with body mass index (BMI) and obesity. Methods: The subjects were Spanish men (n=1547) and women (n=1615) aged 25 - 74 years who were examined in 1999 2000, in a population-based cross-sectional survey in the northeast of Spain (Girona). Dietary intake was assessed using a food frequency questionnaire. Two dietary quality indices, namely the Mediterranean Diet Score (MDS) and the Healthy Eating Index (HEI), were created. Average food prices were calculated. Anthropometric variables were measured. Results: Adjusted linear regression analysis revealed that an increase in 1 Euro (1.25$) of monetary diet costs per day was associated with a change of 0.46 units (P < 0.001) and 2.03 units (P < 0.001) in the MDS and HEI, respectively. The magnitude of the association was similar for both scores after standardization. Subjects who closely adhered to the MDS and HEI paid daily 1.2 Euro (1.50$) (P < 0.001) and 1.4 Euro (1.75$) (P < 0.001) more for food consumption, respectively, than those who weakly adhered to these dietary patterns. Multiple linear regression analysis adjusted for several confounders showed an inverse association of the MDS (P < 0.011) and the HEI (P < 0.001) with BMI. The risk of obesity (BMI >= 30) significantly decreased across quartile distribution of MDS (P=0.004) and HEI (P=0.001). Conclusion: Data showed that a high adherence to the MDS and HEI, both inversely associated with BMI and obesity, led to higher monetary costs as compared to a low adherence. This might be of importance for public health policies in an effort to develop strategies to promote healthy diets preventing weight gain.