Socioeconomic Determinants of Diet Quality on Overweight and Obesity in Adults Aged 40–59 Years in Inner Mongolia: A Cross-Sectional Study

Objectives: This study investigated the relationship of socioeconomic status (SES), diet quality and overweight and obesity in adults aged 40–59 years in Inner Mongolia. Methods: This cross-sectional study was based on the survey of Chronic Disease and Nutrition Monitoring in Adults in Inner Mongolia in 2015. Diet quality was evaluated by the Alternate Mediterranean Diet score (aMeds). SES was measured by household annual income. Generalized estimating equations and path analysis were performed to determine the association of SES, diet quality and overweight and obesity. Results: Among participants, 63.0% had overweight and obesity. In high SES group, 66.4% had overweight and obesity. Higher SES was associated with a higher risk of overweight and obesity (OR = 1.352, 95%CI: 1.020–1.793). And higher aMeds was associated with a lower risk of overweight and obesity (OR = 0.597, 95%CI: 0.419–0.851). There was a positive correlation between SES and the intake of red and processed meat (r = 0.132, p < 0.05). Higher intake of red and processed meat was associated with lower diet quality (β = −0.34). And lower diet quality was associated with a higher risk of overweight and obesity (β = −0.10). Conclusion: In Inner Mongolia, during the period of economic transition, people aged 40–59 years in high SES had poor diet quality, which was related to a higher risk of overweight and obesity.