Comparison of energy expenditure between women with anorexia nervosa in outpatient treatment and healthy controls

Abstract

Objective Resting metabolic rate is an important measure for nutritional monitoring in anorexia nervosa. This study aims to investigate the differences in resting metabolic rate measurements across various methods between underweight and recovered anorexia nervosa patients, as well as healthy controls. Methods Participants were categorized into three groups: active anorexia nervosa, recovered anorexia nervosa, and healthy individuals. Indirect calorimetry, the gold standard for resting metabolic rate measurement, was used to evaluate the performance of the Harris-Benedict, Schebendach, FAO/WHO, and Buchholz equations. Body mass index and fat free mass were also measured. Mean and median resting metabolic rate values across evaluation methods were compared, and Bland-Altman plots along with percent difference tables were employed to compare the different methods. Results In the active anorexia nervosa group, the Buchholz, Harris-Benedict, and FAO/WHO equations overestimated resting metabolic rate, whereas the Schebendach equation did not. In the recovered anorexia nervosa group, Schebendach’s equation underestimated resting metabolic rate, while the other equations, with the exception of FAO/WHO, did not. Bland-Altman analysis supported the adequacy of the Schebendach equation in active anorexia nervosa. In recovered anorexia nervosa, proportional biases observed for the Harris-Benedict, Buchholz, and FAO/WHO equations indicated its inadequacies for this group. Conclusion In patients with active anorexia nervosa, the results indicate that the Schebendach equation may be adequate for estimating resting metabolic rate. However, none of the equations showed adequacy for estimating resting metabolic rate in recovered patients.