Introduction: Phase angle (PhA) derived from bioelectrical impedance analysis reflects cellular integrity and has emerged as a potential marker of metabolic health. Its role in detecting early physiological changes during lifestyle intervention remains underexplored in workplace obesity programmes. Methodology: This longitudinal study included 30 adults with complete paired measurements enrolled in a 12-month workplace lifestyle programme. Body composition was assessed using multifrequency bioelectrical impedance analysis. Measurements included whole-body PhA, body cell mass (BCM), skeletal muscle index (SMI), and extracellular water to total body water ratio. Paired comparisons and correlation analyses were performed. Results: Mean PhA increased modestly from 5.59 ± 0.70° to 5.67 ± 0.69°, although this did not reach statistical significance (p = 0.17). Changes in PhA were not significantly associated with changes in BCM (r = −0.03, p = 0.89). However, baseline PhA demonstrated a moderate positive association with SMI (r ≈ 0.51, p <0.01), suggesting a link between cellular integrity and muscle status. Individual trajectories revealed heterogeneous responses despite minimal weight change. Conclusion Whole-body phase angle provides insight into cellular health beyond conventional anthropometric measures. While short-term changes were modest, PhA may serve as a clinically useful adjunct for monitoring physiological response in obesity management programmes.
Workplace

Introduction: Obesity is a chronic disease characterized by complex alterations in body composition and metabolic health. Traditional reliance on body weight may overlook important physiological adaptations during lifestyle intervention. Methodology: A cohort of 99 participants at programme entry underwent body composition assessment using bioelectrical impedance analysis. Parameters included percent body fat (PBF), visceral fat area (VFA), skeletal muscle index (SMI), and phase angle (PhA). Correlation analyses were performed to explore relationships between adiposity, muscle mass, and cellular health. Results: Participants demonstrated elevated adiposity (PBF 38.9 ± 8.9%; VFA 142.9 ± 56.1 cm²). PhA was inversely associated with VFA (r ≈ −0.23, p <0.05) and positively associated with SMI (r ≈ 0.49, p <0.001). Notably, a subset of overweight individuals exhibited relatively preserved PhA, indicating heterogeneity in metabolic health despite similar adiposity levels. Conclusion Body composition and PhA provide complementary insights into metabolic health beyond body weight. These findings support the role of bioimpedance-derived parameters in identifying metabolic heterogeneity and guiding personalized obesity management.
Body Composition ; Body Weight ; Workplace ; Obesity