A study of high research methods design reported a group RMR mean overestimation error by ~9% in obese males, 30-60 years; representing a group mean overestimation of 166 kcals/day. A study of moderate quality research design reported a group RMR mean overestimation error of 408 kcals/day in males within the same age range. Another moderate research quality design quality reported that the Harris-Benedict equation overestimated group RMR means by 12% and 11% in obese males and females, respectively; and represented errors of 336 kcals/day and 202 kcals/day. In two high quality studies of only females, the Harris-Benedict equation overestimates group mean by ~166 kcals/day and 396 kcals/day. In another study of females and when measured RMR was adjusted for difference in lean body mass, the Harris-Benedict equation underestimated by 233 kcals/day in Caucasian women and slightly overestimated by 35 kcals/day in African-American women.

A high quality study of U.S. residing, non-obese and obese males (ages 19-<50 years) report Harris-Benedict overestimates group mean RMR by 9%. Two neutral quality research design study also report, Harris-Benedict overestimated group mean RMR by 9% in younger age, non-obese, U.S.-residing, males (ages 18-33) and by 10-11% in males, (~21-51 y) representing all weight categories. In the latter study, Harris-Benedict overestimated group mean RMR in non-obese females by 11-14%. The group RMR mean overestimation error ranges from 54-148 kcals/day U.S.-residing individuals, 18-76 years, representing all weight classifications.