Comparison of Predicted and Measured Resting Metabolic Rate Among African American Men and Women

Background: Indirect calorimetry has been established as the gold standard to measure resting metabolic rate (RMR), however, its clinical use is limited and can be very expensive. Therefore, the use of predictive equations are commonly used as an alternative. The objective of the current study was to compare RMR calculated using predictive models versus measured RMR using indirect calorimetry among African-Americans. Methods: African-American men and women, aged 21-70 years participated in the study. Participants were required to attend two study visits for the collection of self-reported and objective measurements of physical activity. Objective measures of physical activity were measured by accelerometer and self-reported physical activity was obtained using the International Physical Activity Questionnaire Long Form (IPAQ-LF). Objective measures of weight were measured using an automatic scale and height by stadiometer. Harris-Benedict, Nelson, Cunningham, Mifflin-St. Jeor, Owen and WHO/FAO/UNU models were used to measure RMR. All statistical analyses were conducted using R (version 4.3.3). The agreement between measured resting metabolic rate (RMR) and predicted RMR from the commonly used equations was assessed using the Bland-Altman method. Results: The study comprised 64 African-American women (n=43, 67.2%) and men (n=19, 29.7%), with a mean age of 55.6 years. The WHO/FAO/UNU weight-and-height (bias = 20.5 kcal/day; 95% CI: -92.8 to 133.7; p = 0.719) and WHO/FAO/UNU weight-only equations (bias =22.7 kcal/day; 95% CI: -90.2 to 135.7; p = 0.688) demonstrated the smallest, non-significant Conclusions: The WHO/FAO/UNU model was more reliable than other models for predicting RMR among African-Americans.