Reexamination of the relationship of resting metabolic rate to fat-free mass and to the metabolically active components of fat-free mass in humans

• Published in: The American journal of clinical nutrition Vol. 55; no. 4; pp. 790 - 794
• Main Authors: Weinsier, RL, Schutz, Y, Bracco, D
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.04.1992; American Society for Clinical Nutrition
• Subjects: Adolescent; Adult; Aged; analisis estadistico; analyse statistique; Basal Metabolism; Biological and medical sciences; Body Composition; Body Weight; Child; Child, Preschool; energia; energie; energy; energy expenditure; Energy Metabolism; fat-free mass; Fundamental and applied biological sciences. Psychology; Humans; Infant; Intermediate and energetic metabolism; lean body mass; metabolism; metabolisme; metabolismo; Metabolisms and neurohumoral controls; Middle Aged; Obesity; Obesity - metabolism; peso; poids; Regression Analysis; Resting metabolic rate; statistical analysis; Vertebrates: anatomy and physiology, studies on body, several organs or systems; weight; body weight; fat-free mass; Resting metabolic rate; body composition; energy expenditure; obesity; Human; Energy metabolism; Body weight; Adolescent; Adult; Infant; Basal metabolism; Child; Statistical study; Age; Body composition
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/55.4.790

The ratio of resting metabolic rate (RMR) to fat-free mass (FFM) is often used to compare individuals of different body sizes. Because RMR has not been well described over the full range of FFM, a literature review was conducted among groups with a wide range of FFM. It included 31 data sets comprising a total of 1111 subjects: 118 infants and preschoolers, 323 adolescents, and 670 adults; FFM ranged from 2.8 to 106 kg. The relationship of RMR to FFM was found to be nonlinear and average slopes of the regression equations of the three groups differed significantly (P < 0.0001). For only the youngest group did the intercept approach zero. The lower slopes of RMR on FFM, at higher measures of FFM, corresponded to relatively greater proportions of less metabolically active muscle mass and to lesser proportions of more metabolically active nonmuscle organ mass. Because the contribution of FFM to RMR is not constant, an arithmetic error is introduced when the ratio of RMR to FFM is used. Hence, alternative methods should be used to compare individuals with markedly different FFM.