BACKGROUND: The beneficial impact of the traditional Mediterranean diet pattern on adiposity is still under debate, and this has never been assessed in a developing Mediterranean country. OBJECTIVES: To assess the relationships between adherence to a traditional Mediterranean diet and adiposity indexes, that is, body mass index (BMI) and waist circumference (WC), in a sample from rural Lebanon. DESIGN: A sample of 798 adults, aged 40-60 years, was selected in continental rural areas of Lebanon for a cross-sectional study. The questionnaire included socio-demographic, anthropometric and dietary sections. The daily consumption frequencies of selected food groups, categorized as positive or negative components, were calculated based on a food frequency questionnaire. Adherence to the Mediterranean diet was assessed using six a priori scores; including the widely used Mediterranean diet score (MDS). Associations between diet scores and BMI and WC were assessed. RESULTS: Overall, the diet of the study sample only partially matched the traditional Mediterranean diet. A total of 17.0% of men and 33.7% women were obese. The MDS was negatively associated (P<0.05) with WC, but not BMI, in men and women. The constructed composite Mediterranean score combining positive components of the diet (whole cereals, vegetables, legumes and fruit, olive oil and fish) and negative components adapted to this sample (refined cereals and pastries, and liquid sweets) was consistently and negatively associated with both BMI and WC for men and women in multivariate models. A 2-point increase in that score was associated with a decrease in BMI of 0.51 and 0.78 kg m(-2) and a decrease in WC of 2.77 and 4.76 cm in men and women, respectively. CONCLUSION: The results demonstrate that a Mediterranean diet is negatively associated with obesity and visceral adiposity in a rural population of a developing Mediterranean country.