![]() Similarly, Mifflin et al., 12 and Owen et al., 13 have developed predictive equations for overweight and obese Caucasians. ![]() Among these are equations of Liu et al., 8 and Yang et al., 11 which have been developed predominantly for healthy Asian subjects. Subsequently, improved equations have been developed in an attempt to improve estimates of BMR and reflect racial variations. 10 However, results of BIA may be influenced by the hydration status, prandial/fasting state, exercise, diuretic use, menstrual period, ethnicity, age or body shape. Bioelectrical impedance analysis (BIA) determines the electrical impedance or resistance to flow of an electric current through body tissues, to estimate total body water, which can then be used to determine fat-free mass. While fat-free mass is more difficult to measure than body weight, modern technology has resulted in techniques that are efficient, inexpensive and reliable for use in clinical setting. Moreover, literature also supports the inclusion of fat-free mass as a variable in measuring BMR due to its strong correlation with BMR. 7- 9 These prediction equations estimate BMR by incorporating the patient’s height, weight, gender and age, but not race. 3 Additionally, previous studies show that the predicted BMR equations derived from Caucasian subjects overestimated the BMR of the Asian subjects. As a consequence, they do not permit a valid estimation of BMR in subjects with obesity. These equations generally take into consideration anthropometric variables such as age, body weight and height of the subjects. 6 However, in spite of their widespread use, previous studies have found that prediction equations were inaccurate in various clinical settings. The most widely used prediction equation is the Harris-Benedict Equation (HBE), which was developed in 1918 as a simple, easy-to-use and universally available method for calculation of BMR. ![]() Thus, the majority of BMR estimates for weight loss interventions rely on BMR prediction equations. Although IC is extremely valid, it is not widely available, has a high cost, is time consuming and requires specialized personnel for its execution. 4 The gold standard for BMR measurement is IC, whereby oxygen consumption and carbon dioxide production in expired air are directly measured for calculation of energy expenditure. 3 The measurement of BMR via prediction equations, bioelectrical impedance analysis (BIA) and indirect calorimetry (IC) is a common practice in weight clinics and for research. There are several methods to measure energy expenditure, but there is no consensus about which is the most accurate for specific populations. 1 Since the BMR represents the major component of daily energy expenditure in humans, it is an important calculation for developing, understanding and executing weight-related interventions. Other factors that affect the BMR includes age, sex, diet, thyroid status, exercise, and stress. Several studies reported that fat-free mass or the lean body mass plays a major role in the variations in BMR. The measurement of basal metabolic rate (BMR), defined as the energy required for performing vital body functions at rest, is the largest component of energy expenditure.
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