Energy Balance Assessment in a Whole-Room Indirect Calorimeter: Protocol for a Prospective Validation Study (Preprint)

BACKGROUND Long-term body weight is regulated by the balance between energy intake and energy expenditure (EE). Although weight stability requires energy balance, achieving and maintaining such balance in everyday life is challenging. Weight loss occurs when EE consistently exceeds energy intake, whereas a sustained positive energy balance promotes weight gain which may lead to obesity. Whole-room indirect calorimetry enables precise 24-h assessment of total EE and its components. Achieving energy balance within a whole-room indirect calorimeter (WRIC) represents a substantial challenge and depends critically on stringent clinical standardization as well as robust technical performance to ensure accurate estimation of energy requirements. OBJECTIVE To achieve energy balance within a WRIC and to characterize the technical performance of two newly installed WRIC systems. METHODS Healthy subjects, aged 18 to 65 years with a body mass index of 18.5 to 0.80, assuming a standard deviation of 200 kcal. The final analyses will include energy balance, changes in body weight, components of EE, ad libitum energy intake, and circulating hormones involved in appetite regulation and satiety. CONCLUSIONS This trial evaluates whether energy balance can be achieved during repeated stays in a WRIC and provides a detailed assessment of the performance of two newly installed WRIC systems.