Predicted vs. Actual Resting Energy Expenditure and Activity Coefficients: Post-Gastric Bypass, Lean and Obese Women

Abstract

Determining daily energy requirements to help guide weight control involves all components of Total Energy Expenditure (TEE): Resting Energy Expenditure (REE), Physical Activity Energy Expenditure (PAEE), and the Thermogenic Effect of Food (TEF). However, precise measurement of TEE mandates sophisticated equipment not readily available outside research or clinical settings. The Harris-Benedict (HB), [1] Mifflin St. Jeor (MSJ), [2] and the Food and Agriculture Organization/ World Health Organization/ United Nations University (FAO/WHO/UNU)[3] are REE predicting equations widely used in different populations [4-6]. These equations consider factors such as weight, height, age, and gender. The predicted REE is then multiplied by a PA coefficient for an estimate of TEE (Table 1). These coefficients have been derived by subtracting REE measured with indirect calorimetry from the TEE measured with the doubly labelled water technique [3,7,8]. Therefore, PA coefficients account not only for PAEE but also the TEF. However, there are inconsistencies in the selection and recommendation of PA coefficients for different equations (Table 1). Specific PA coefficients are based on the PA level of each participant, usually determined by self-reports and dietitian's experience. Because PAEE is the most variable component of TEE, the impact of PA coefficients based on self-report vs. objective PA assessment must be evaluated. After gastric bypass surgery REE declines in direct association with weight loss [9-11], and REE prediction equations remain well correlated with measured REE (REE-m) in this population. Flancbaum et al. [12] showed that HB equation predicted 90-101% of the REE-m by indirect calorimetry from pre-to 6-months post-surgery and 107-111% from 12-24 months post-surgery; during which gastric bypass patient's weight decreased 96 to 146 kg. Among obese individuals, Prado-de Oliveira et al. [13] reported that HB equation predicted REE-m; however, prediction was 8% lower. More recently, Ullah et al. [14] observed that HB equation overestimated REE by 10% in morbidly obese adults,