Resting Energy Expenditure Can Be Assessed by Fat-Free Mass in Female Athletes Regardless of Body Size

Abstract

Summary Energy requirements can be estimated from resting energy expenditure (REE). However, little is known about factors influencing REE in Japanese female athletes. This study was performed to evaluate the relationship between REE and body composition in Japanese female athletes with a wide range of body sizes. Ninety-three athletes (age 20.3 Ϯ 1.2 y, height 162.8 Ϯ 6.4 cm, body weight (BW) 57.0 Ϯ 9.2 kg, fat-free mass (FFM) 45.4 Ϯ 6.2 kg) were classified into three groups according to BW: small-size (S) ( n ϭ 34), medium-size (M) ( n ϭ 34), and large-size (L) ( n ϭ 25). Systemic and regional body compositions (skeletal muscle (SM), fat mass (FM), bone mass (BM), and residual mass (RM)) were estimated by dual energy X-ray absorptiometry (DXA). Measured resting energy expenditure (REEm) was evaluated by indirect calorimetry. Marked differences were found in REEm (S: 1,111 Ϯ 150, M: 1,242 Ϯ 133, L: 1,478 Ϯ 138 kcal/d), and systemic and regional body compositions among the three groups. REEm was strongly correlated with FFM, and absolute values of RM and SM increased significantly according to body size. There was good agreement between REEm and estimated REE (REEe) from the specific metabolic rates of four major organ tissue level compartments. These data indicate that REE for female athletes can be attributed to changes in organ tissue mass, and not changes in organ tissue metabolic rate. That is, change in REE can be explained mainly by the change in FFM, and REE can be assessed by FFM in female athletes regardless of body size. Key Words female athletes, resting energy expenditure, body composition, body size, fatfree mass Energy balance is a primary concern in most female athletes. Much of the effort of training can be lost when energy intake is insufficient to match that expended, as both body fat and body protein will be used for energy. In addition, if energy intake is limited or restricted, the ability to obtain other essential nutrients necessary for optimal sport performance and good health will be compromised. Previous studies suggested that chronic energy deficit have been implicated in health problems of female athletes such as disturbance of menstruation, osteopenia, eating disorders and anemia ( 1-3 ). Therefore, it is essential to properly manage the energy intake matched with energy requirement in female athletes.Energy requirement can be estimated from resting energy expenditure (REE). Estimated energy requirement (EER) is calculated using the estimation equation based on REE in the Dietary Reference Intakes for Japanese, 2010 (DRIs) ( 4 ). In most sedentary healthy adults, REE accounts for approximately 60% of total daily energy expenditure ( 5-7 ). It is well documented that REE is influenced by age, sex, body size, and body composition, including an individual's fat-free mass (FFM) or fat mass (FM) ( 8-10 ). In fact, these factors are usually included in prediction equations for REE ( 9 , 11 , 12 ), and three of these variables (age, sex, and FFM) generally account for 80% of the variabili...

Fat-Free Mass Can Be Utilized to Assess Resting Energy Expenditure for Male Athletes of Different Body Size

“…However, the explanation for this finding has yet to be uncovered. Taguchi et al (9) reported that organ-tissue mass is responsible for determining REE, and thus it can be accurately measured by FFM. The investigator utilized Japanese female athletes over a wide range of body sizes.…”

“…The four organ-tissue compartments have a specific metabolic rate; BM and AT have relatively smaller weight-related metabolic rates (2.3 and 4.5 kcal/kg/d), on the other hand, SM and RM have higher metabolic rates (13 and 54 kcal/kg/d) (7). REEe can be obtained utilizing these metabolic rates with the actual mass of each organ-tissue compartment based on the previously established model (9,11). According to previous studies which used the same organ-tissue REE prediction method, the correlation coefficients between REEm and REEe were 0.75 (pϽ0.001) for untrained males and females, and 0.77 (pϽ0.01) for Japanese female athletes (7,9).…”

“…However, there has been little research investigating the relationship between FFM and REE at the organ-tissue level on male athletes, so the details of this relationship remain unclear. For female athletes, Taguchi et al ( 9 ) reported that FFM can predict REE since between-individual differences in REE can be explained by differences in the metabolically active organ-tissue mass. However, for male athletes, the accuracy of an estimation of REE based on FFM has not been studied in detail.…”

The Validity of Body Composition Measurement Using Dual Energy X-Ray Absorptiometry for Estimating Resting Energy Expenditure

“…In addition, as for the four component model of REE prediction, Taguchi et al (2011) evaluated that the relationship between REE and body composition in Japanese female athletes with a wide range of body sizes. Their results indicated, in good agreement with previous study (Bosy-Westphal et al, 2004), that REE for female athletes with a wide range of body sizes can be attributed to changes in organ tissue mass, and not changes in organ tissue metabolic rate.…”

“…The data used for the current analysis were collected from different 3 experimental studies that followed a similar methodology (Usui et al, 2009;Taguchi et al, 2011;Hasegawa et al, 2011). Total of 288 healthy women (216 young women; age: 21.8 ± 2.0 (18-29) years and 72 elderly women; age: 63.3 ± 6.4 (50-77) years) were recruited for the study.…”