Measured Vs. Predicted Basal Energy Expenditure in Obese Women

Abstract

The purpose of this study was to determine if actual, ideal, or adjusted body weight should be used in the Harris-Benedict equation (HBE) to estimate basal energy expenditure (BEE) in obese females and to determine if the Ireton-Jones equation (IJE) accurately estimates BEE in obese females. Nineteen healthy, premenopausal, obese (>125% IBW) females, ages 18-39 completed a questionnaire detailing demographic and medical history information. BEE was determined by open-circuit indirect calorimetry, and weight, height, and body composition (bioelectrical impedance) were measured. BEE was calculated using the HBE with ideal body weight (IBW), actual body weight (ABW) and adjusted body weight (AdBW). The mean BMI and percent body fat of subjects were 35.5+8.4 and 41.2+5.0, respectively. There was no difference (p<0.05) between measured BEE (1359±252 kcalories) and BEE calculated with HBE using IBW (1416±50). BEEs calculated with HBE using ABW (1755±218) and AdBW (1416±50) were significantly higher than measured BEE, as was calculated with IJE (1869±257). When mildly obese (Class I) subjects were dropped from the analysis, BEE by HBE using AdBW was no longer different from measured BEE. BEE was significantly (P<0.05) correlated with all predicted BEEs except for the BEE predicted with HBW using IBW. In conclusion, the HBE using IBW is the best equation to predict BEE in mildly (Class I) obese women, but HBE using AdBW is better for women with Class II or greater obesity. Equations specific for the obese population, categorized by degree of obesity, need to be developed.