| Paper title: |
Body mass index versus body fat percentage: implications for accurate assessment of weight status |
| DOI: | https://doi.org/10.4316/SAM.2026.0106 |
| Published in: | Volume XIX issue 1/ 2026 |
| Publishing date: | 2026 |
| Pages: | |
| Author(s): | Holubiac Iulian Ștefan |
| Abstract. | Body Mass Index (BMI) is widely used to classify weight status, yet it does not distinguish between fat mass and lean mass. Therefore, BMI may misclassify individuals when adiposity is assessed directly. This study aimed to examine the relationship and discrepancies between BMI and body fat percentage (Fat %) in the evaluation of weight status. Twenty-three females were assessed for body composition using a Tanita bioelectrical impedance analyzer. BMI was calculated from height and body mass, and body fat percentage was obtained via bioelectrical impedance analysis. BMI and Fat % were further categorized using standard cut-off values. Associations between categorical variables were examined using Crosstabs with Chi-square and Fisher’s Exact Test. Pearson correlations were computed among age, BMI, and Fat %. A multiple linear regression analysis was conducted to determine whether BMI and age predict Fat %. Crosstabulation showed a significant association between BMI categories and Fat % categories (p = .003), indicating general agreement between classification methods. However, Pearson correlation between BMI and Fat % was moderate and not statistically significant (r = .37, p = .08). The regression model including BMI and age explained 14.8% of the variance in Fat % and was not significant, F(2, 20) = 1.73, p = .202. BMI showed a positive but non-significant contribution (B = 0.67, p = .114), while age had no meaningful effect (B = 0.20, p = .656). Although BMI categories correspond broadly with body fat classification, BMI does not accurately predict individual body fat percentage. These findings support the limitation of BMI as a standalone indicator of adiposity and highlight the importance of direct body composition assessment for evaluating weight status. |
| Keywords: | body mass index (BMI), body fat percentage, bioelectrical impedance analysis (BIA), body composition, adiposity, weight status classification, fat mass, lean body mass. |
| References: |
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