Introduction Poor nutritional status might impact in unintentional weight loss and decreased muscle mass and strength. The levels of physical fitness (PF) is a predictor of chronic diseases in future years. Also, evaluation of fitness is an essential factor for duty in occupations which are sensitive to time and emergency reaction. Since there is no literature that study the association between dietary patterns and the PF level in physically strenuous occupations, the aim of this study was to examine the relationship between dietary patterns and the PF level in military staffs.

Methods This cross-sectional study was carried out in military zones of Iran. Typical dietary intakes were assessed by using a semi-quantitative food-frequency questionnaire. Mediterranean diet (MD) score and healthy diet indicator (HDI) score were calculated. PF tests were designed to test the muscular strength, endurance and cardiovascular respiratory fitness (CRF).

Results Mean age of participants was 33.03±4.65 in the study. Referring to the performance in the PF tests, there was a correlation between tertiles of MD (OR 4.37, p=0.048) and HDI (OR 5.21, p=0.019) scores and suitable PF level in the crude and confounder adjusted models. Also, a negative relationship was found between body mass index and waist circumference with fitness score.

Conclusions We concluded that accompanying a medium or high adherence to a healthy dietary pattern will have an impact on good level of PF and will result in a better working power and long-term health consequences among physically strenuous occupations.