Does Body Roundness Index Reflect Body Composition Changes After Behavioral Weight Loss Programs?

The Body Roundness Index (BRI) was introduced to quantify body shape independent of height (Thomas et al., 2013). The BRI may overcome some of the limitations of other anthropometric measures utilized to indicate level of obesity such as Body Mass Index (BMI) that may not be sensitive to changes in body fat mass or lean mass. The BRI includes waist circumference (WC) and height to determine the degree of circularity of the body with greater BRIs representing “rounder” individuals. PURPOSE: To determine whether BRI represented body composition changes after completion of Behavioral Weight Loss Programs (BWLPs) similar to other commonly employed anthropometric measures. METHODS: Data from multiple studies by Carels et al. (2008, 2009, 2010, 2011) were combined to investigate changes in anthropometrics for participants who were overweight or obese measured pre- and post-BWLPs: (N = 127; Men, n = 31; Women, n = 96; Age = 49 ± 13 yrs.). ANOVAs (Time by Sex), t-tests, simple and multiple linear regressions, and difference scores (Δ, pre- vs. post-BWLPs) were calculated for BRI, BMI, Body Weight (BW), % Body Fat (%BF), Visceral Adipose Tissue and WC. RESULTS: Both BRI and %BF were significantly less post-BWLPs (p < .001), with BRI decreasing from Pre: 5.76 +/- 1.99 to Post: 5.37 +/- 1.97. A significant main effect of Sex on BRI was observed (p = .01). Post hoc t-tests showed that both women (p < .001) and men (p = .004) had significant decreases in BRI over time. All other anthropometric variables were significantly different post-BWLP. ΔBRI was significantly related to the Δ%BF (R = .221; p = .013). When this relationship was analyzed by Sex, ΔBRI for women was significantly related to Δ%BF (R = .242; p = .018), however this relationship was not significant for men (R = .205; p = .269). Similarly, PreBRI was significantly related to Δ%BF regardless of sex (R = .200; p = .025) and for women (R = .264; p = .010), but not for men (R = .100; p = .592). CONCLUSION: For BWLPs participants, BRI was representative of other anthropometric measures typically utilized to monitor BW and body composition changes over time to quantify success in BWLPs. Differences in some of these anthropometric measures may reflect selective body composition changes in men and women after BWLPs.