Association Between the Dietary Inflammatory Index and Resting Metabolic Rate per Kilogram of Fat-Free Mass in Overweight and Obese Women

Background: A low Resting Metabolic Rate (RMR) as a risk factor for weight gain can be affected by many factors. However, the role of Dietary Inflammatory Index (DII) in RMR is still unknown. This study was designed to examine the association between resting metabolic rate per kilogram of fat-free mass and DII. Methods: This cross-sectional study was conducted among 304 Iranian overweight and obese women aged 18-50 years. RMR was measured by indirect calorimetry. Bioelectrical Impedance Analysis (BIA) was used to determine Fat Free Mass (FFM) and other body composition parameters. A validated 147-item FFQ was used to compute dietary inflammatory index. Results: Participants that consumed more pro-inflammatory foods, compared to those with lower intake had significantly a lower odds ratio for increased RMR/FFM (OR: 0.40; 95% CI: 0.16-0.91; p=0.01). Moreover, after adjusting for potential confounders, a significant inverse association between DII and RMR/FFM was observed in overweight women (OR: 0.31; 95% CI: 0.09-0.98; p=0.04). Conclusion: In this study, an inverse association between DII score and RMR/FFM in overweight women was observed. Further studies, in particular prospective cohorts with long-term follow-up, are required to confirm these findings.