Association of plant-based dietary patterns with psychological profile and obesity in Iranian women

A bidirectional association exists between psychological disorders and obesity. Also, diet could impact on both of these disorders. The aim of this study was to evaluate the association between plant-based dietary patterns and psychological profile and obesity. This cross-sectional study was performed in a sample of 435 Iranian women. A validated and reliable semi-quantitative food-frequency questionnaire was used to collect dietary data. Three dietary indices including an overall plant-based diet (PDI), healthful plant-based diet (hPDI), and unhealthful plant-based diet (uPDI) were determined. Body mass index (BMI) and waist circumference (WC) were used to define general and abdominal obesity, respectively. Psychological profile status was determined from the DASS-21 questionnaire. We found that higher uPDI scores increased the odds of overall (PDI: 2.62; 95% CI 1.28–5.35, Ptrend = 0.01) and abdominal (PDI: 2.36; 95% CI 1.11–5.02, Ptrend = 0.03) obesity in comparison with lower scores. Moreover, an inverse association was observed between higher PDI and hPDI scores and depression (PDI: 0.41; 95% CI 0.23–0.71, Ptrend = 0.001, hPDI: 0.44; 95% CI 0.25–0.76, Ptrend = 0.003), anxiety (PDI: 0.56; 95% CI 0.33–0.94, Ptrend = 0.03, hPDI: 0.55; 95% CI 0.33–0.94, Ptrend = 0.03), and psychological distress (PDI: 0.44; 95% CI 0.26–0.75, Ptrend = 0.003, hPDI: 0.49; 95% CI 0.29–0.82, Ptrend = 0.009). For uPDI, higher scores were associated with depression (uPDI: 1.91; 95% CI 1.03–3.55, Ptrend = 0.03). A plant-based diet, particularly healthful-rich plant foods were inversely associated with psychological disorders. Furthermore, unhealthy plant foods were associated with increased risk of obesity as well as depression.