Two Functional Calorimetric Chambers in France Complete the Room Indirect Calorimetry Operating and Reporting Standards (RICORS) 1.0 Guide List

Validation of energy expenditure and macronutrient oxidation measured by two new whole-room indirect calorimeters

OBJECTIVE

The aim of this study was to validate two new whole-room indirfect calorimeters according to Room Indirect Calorimetry Operating and Reporting Standards (RICORS 1.0).

METHODS

For technical validation, 16 propane combustion tests were performed to determine accuracy and precision of energy expenditure (EE) and ventilation rates of oxygen (VO₂ ), carbon dioxide (VCO₂ ), and respiratory exchange ratio (VCO₂ /VO₂ ). For biological validation, eight participants (mean [SD], age 24.1 [2.5] years; BMI 24.3 [3.1] kg/m² ) underwent four 24-hour protocols under highly standardized conditions: (1) isocaloric sedentary, (2) fasting sedentary, (3) isocaloric active, and (4) fasting active. Reliability (coefficients of variation [CV]) and minimal detectable changes (MDC) were calculated for 24-hour EE, sleeping metabolic rate (SMR), physical activity energy expenditure (PAEE), thermic effect of food (TEF), and macronutrient oxidation rates.

RESULTS

Technical validation showed high reliability and recovery rates for VO₂ (0.75% and 100.8%, respectively), VCO₂ (0.49% and 100.6%), and EE (0.54% and 98.2%). Biological validation revealed CV and MDC for active conditions of 1.4% and 4.3% for 24-hour EE, 1.7% and 5.9% for SMR, and 30.2% and 38.4% for TEF, as well as 5.8% and 10.5% for PAEE, respectively. Mean CV and MDC for macronutrient oxidation rates were 9.9% and 22.9%, respectively.

CONCLUSIONS

The precision of 24-hour EE and SMR was high, whereas it was lower for PAEE and poor for TEF.

Association of protein-energy partitioning with body weight and body composition changes in adolescents with severe obesity

BACKGROUND/OBJECTIVES

Body composition and protein-energy partitioning changes are important factors of body weight regulation, but have not been studied in the context of clinical obesity treatment setting. Thus, the aim of the present study was to investigate the pattern of body weight loss, body composition, and energy partitioning changes during a 9-month multidisciplinary weight loss program and 4-month follow up and to test the associations among these changes in adolescents with severe obesity.

SUBJECTS/METHODS

Twenty-five adolescents (14.1 ± 1.5 years old; 13 girls) with severe obesity joined a pediatric obesity center for a 9-month inpatient multidisciplinary weight loss program. All participants performed body composition assessment (i.e. fat mass-FM, and fat-free mass-FFM) and completed a 36-h session in indirect calorimetric chamber before the start (T0), at the end of the intervention (T1) and 4 months follow-up to the intervention (T2). The protein-energy partitioning (P ratio) was calculated as urinary nitrogen loss/total energy expenditure over 24 hours.

INTERVENTIONS

9-month individualized multidisciplinary weight loss program consisting of lifestyle education, psychological support, physical activity, and dietary intervention.

RESULTS

Initial P ratio was positively associated with changes in body weight from T0 to T1 (p = 0.038). The changes in FFM/FM were negatively associated with body weight changes in boys (p = 0.006) from T0 to T1 and in girls (p < 0.001) from T1 to T2. Urinary nitrogen excretion (p < 0.001) and total energy expenditure (p < 0.001) significantly decreased during the weight loss program while the P ratio did not significantly change.

CONCLUSION

The present results suggest that baseline and changes in energy partitioning may be associated with changes in body weight in adolescents with severe obesity. In addition, sexual dimorphism in these patterns of change suggest the need for specific dietary and physical activity strategies in boys and girls to optimize body weight loss and to prevent or slow weight regain.