Correlation between body composition and gold-standard basal metabolic rate in healthy young adults

Introduction: This pilot study aimed to investigate the correlation between body composition parameters and gold-standard measured Basal Metabolic Rate(BMR) in healthy young adults. Methods: Fifteen healthy participants aged 20-34 years were recruited. BMR was measured using indirect calorimetry, and body composition (including body fat percentage, fat-free mass, skeletal muscle mass, visceral fat area, etc.) was assessed using a medical-grade body composition analyser. Pearson correlation analysis was performed to examine the relationships between body composition variables and BMR. Results: The participants had a mean body mass index of 24.0 ± 1.6 kg/m² and a mean BMR of 1566.3 ± 228.5 kcal/day. Fat-free mass showed the strongest positive correlation with BMR (r = .891, p < .001), followed by total muscle mass (r = .885, p < .001) and skeletal muscle mass (r = .879, p < .001). All segmental muscle mass indices were strongly positively correlated with BMR (all p < .001), with lower limb muscle mass (right: r = .875; left: r = .878) showing slightly stronger correlations than upper limb muscle mass (right: r = .852; left: r = .846). In contrast, body fat percentage (r = -.324, p = .198) and visceral fat area (r = -.064, p = .812) showed no significant correlations with BMR. Conclusion: Fat-free mass and skeletal muscle mass (including segmental muscle mass) show the strongest positive associations with BMR in this sample of healthy young adults. Lower limb muscle mass exhibits a marginally stronger association with BMR than upper limb muscle mass, which may be attributed to the larger muscle volume of the lower limbs. These findings highlight the importance of assessing body composition strategies. This is a pilot study with a small sample; results are preliminary and require validation in larger cohorts.