Is Metabolic Rate Measurement Useful in Nonacute Settings?

Abstract

LEARNING OUTCOME: To identify the problems associated with predicting energy requirements and a method for measuring metabolic rate.Weight management clients often ask: Is my metabolic rate normal? In most cases there is not equipment available to provide an objective measurement of metabolic rate such as can be accomplished using indirect calorimetry. Over the past three years, 39 males who entered a nationally recognized weight management program have had their metabolic rates measured (MRM) as an optional part of the program. MRM's were measured using a portable metabolic cart which allows clients to be measured at rest, prior to beginning their daily activities on site. Clients MRM's were compared to those estimated from the Harris-Benedict equations(HBE) using actual body weight (ABW) and ideal body weight (IBW). The HBE are used as the starting point in predicting maintenance calories and therefore weight loss calorie requirements. Overall, participants were 33% above IBW ranging from 7-94% above IBW and when all participants data was grouped together there were no correlations between MRM and HBE-IBW or HBE-ABW. Clients were stratified according to their percentages above IBW: Gp 1 ≤20%, n = 13; Gp 2 >21%≤30%n=10; Gp 3 >31 ≤ 50%n=10; Gp4 >51%n=6 and MRM was compared to HBE calculated using ABW and IBW for each group. In conclusion: MRM was accurately predicted by HBE whether ABW or IBW for Gp 1; however HBE-IBW did not correlate with MRM for any of the other groups. HBE-ABW correlated with MRM for GPs 2 and 4, but not for Gp 3. For clients MRM was more accurately predicted using ABW rather than IBW in the HBE. For Gp 3 who were betwenn 31 and 50% above IBW, neither HBE-IBW or ABW was accurate in predicting MRM. An objective measurement of metabolic rate provides both the dietitian and the client with the information to develop a program which will provide for the client's individualized metabolic needs and thereby a greater potential for long-term success.