Background and Objectives: Healthy eating index (HEI), diet quality index (DQI), Mediterranean dietary score (MDS), and diet diversity score (DDS) are among the most important diet quality indices which are used for evaluation of health and quality of diet. The objective of this study was to investigate the relationship between diet quality indices and eating habits in adults living in Shiraz.
 Materials & Methods: This cross-sectional study was conducted on 438 individuals aged 20-50 years from households living in Shiraz. Information were collected for dietary intakes using a validated 168-item semi-quantitative food frequency questionnaire, and for eating habits, including questions on the frequency of breakfast, dinner, snacks, fried, and fast foods, through face to face interviews. Diet quality indices including HEI, DQI, MDS, and DDS were calculated using validated methods. The relationship between eating habits and diet quality indices was evaluated with linear regression.
Results: After adjustments for age, sex, and body mass index, breakfast consumption was positively associated with all dietary indices but dinner consumption was inversely associated with HEI and MDS (p=0.01). Snacking frequency was positively associated with HEI, DQI, and DDS (p=0.001). Fast food consumption had inverse association with HEI, DQI, and MDS (p<0.001-0.03). Likewise, consumption of fried foods was inversely associated with DQI (p=0.01). Consumption of restaurant foods had no association with diet quality indices. Salt intake had inverse association with HEI and DQI (p<0.001-0.01).
Conclusion: A significant association was observed between diet quality indices and healthy eating habits. Compared to DDS, the indices of HEI, DQI, and MDS had more relationships with eating habits.