The purpose of this study was to investigate whether weight-stable chronically energy-deficient subjects exhibit evidence of metabolic adaptation and to establish whether international predictive equations overestimate the basal metabolic rate (BMR) of tropical populations. BMR, body weight, height, and fat-free mass (FFM) by underwater weighing were measured in healthy, physically active urban dwellers of low socioeconomic status (178 men and women aged 22-38 y) in Bangalore, Southern India. Subjects were selected on the basis of body mass index (BMI; in kg/m2) and classified in three groups: severely undernourished (BMI < 17.0; n = 30 men, n = 25 women), marginally undernourished (BMI = 17.0-18.5; n = 31 men, n = 30 women), and well nourished (BMI > 18.5; n = 27 men, n = 35 women). The BMR of the well-nourished group, expressed in absolute terms (6.20 and 5.18 MJ/d for men and women, respectively), was significantly higher (P < 0.000) than that of the severely undernourished group (5.72 and 4.64 MJ/d for men and women, respectively). Normalizing BMR for either body weight or FFM by analysis of covariance abolished all differences. The mean BMR of the low-BMI study group was substantially higher (11-14%) than reported previously for undernourished Indian adults. The BMR of both men and women, regardless of their nutritional status, was accurately estimated by age- and sex-specific FAO/WHO/UNU equations. These findings suggest the absence of an enhanced metabolic response in weight-stable chronically undernourished adults. This is in contrast with earlier reports, and supports more recent views. The study also provides evidence of the absence of ethnic-specific energy turnover in Indians.

Total body water (TBW) obtained by deuterium dilution (TBWD) in 45 adult Indian males of low body mass index was compared with values obtained from bioelectrical impedance (TBWImp) and two anthropometry-based prediction equations. Bioelectrical impedance significantly underestimated TBW when compared with deuterium dilution, by 2.75 SD 2.86 kg. Comparisons of the anthropometry-based prediction equations demonstrated that TBW was overestimated by 0.87 SD 2.49 kg, and 2.47 SD 2.57 kg, respectively. Since all parameters in the bioelectrical impedance method were standardized, the difference in the values could have been because of the equation used. Therefore, a fresh equation for the measurement of TBW by the bioelectrical impedance method was derived using the variables of height2/impedance and weight. New prediction equations for TBW were also derived based on anthropometric variables of weight and height. Body weight has the greatest influence in the prediction equations for TBW, and the equation derived was TBW (kg) = 0.533 x body weight (kg) + 3.77, SEE = 2.4 kg. Using height2/impedance gave the relationship: TBW (kg) = 0.568 body weight-0.04 height2/impedance + 4.35, SEE = 1.9 kg.