The Harris-Benedict Studies of Human Basal Metabolism: History and Limitations

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Abstract

In the early part of the 20th century, numerous studies of human basal metabolism were conducted at the Nutrition Laboratory of the Carnegie Institution of Washington in Boston, Mass, under the direction of Francis G. Benedict. Prediction equations for basal energy expenditure (BEE) were developed from these studies. The expressed purpose of these equations was to establish normal standards to serve as a benchmark for comparison with BEE of persons with various disease states such as diabetes, thyroid, and other febrile diseases. The Harris-Benedict equations remain the most common method for calculating BEE for clinical and research purposes. The widespread use of the equations and the relative inaccessibility of the original work highlights the importance of reviewing the data from which the standards were developed. A review of the data reveals that the methods and conclusions of Harris and Benedict appear valid and reasonable, albeit not error free. All of the variables used in the equations have sound physiologic basis for use in predicting BEE. Supplemental data from the Nutrition Laboratory indicates that the original equations can be applied over a wide range of age and body types. The commonly held assumption that the Harris-Benedict equations overestimate BEE in obese persons may not be true for persons who are moderately obese. J Am Diet Assoc. 1998;98:439-445.

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Study Population

The BEE data published in 1919 were collected by the Nutrition Laboratory (dissolved in 1945) of the Carnegie Institution in Washington, DC, over a period of perhaps 10 years, starting before 1909 and ending around 1917. The purpose of collating and analyzing these data was to determine metabolic constants for healthy people to compare with the metabolic rates of persons with various diseases then being studied (diabetes, thyroid disease, and various febrile diseases). The 1919 study sample was

Study Methods and Design

For the 1919, 1928, and 1932 series of data collections, subjects traveled to the test site, arriving at approximately 8 am, having not eaten during the previous 12 hours. These studies therefore are not strictly basal. To minimize the effects of the journey on BEE, subjects initially laid still on a bed or couch for 30 minutes. Full muscle repose was ascertained objectively by attachment of a pneumograph to the bed or to the patient. Subjects in the 1935 series were studied in their homes,

Study Techniques

Indirect calorimetry was used to measure gas exchange, which was then converted mathematically to energy expenditure using the constants of Zuntz and Schumberg (5), sometimes using the actual respiratory quotient, sometimes assuming a respiratory quotient of 0.85 (if carbon dioxide production or oxygen consumption were not available), but usually calculating energy expenditure directly from oxygen consumption. In their calculations, Harris and Benedict took a then common shortcut in converting

Results of Calorimetry Studies

Harris and Benedict's partial correlation analysis revealed that weight, height, and age had independent correlations with BEE (Table 2) and so were used in multiple regression analysis (one of the first applications of this statistical technique to human physiology) to yield the equations in use today:Men:BEE(kcal/d)=66.4730+13.7516(weight)+5.0033(height)−6.7550(age)r2=0.75,F3,132=135.2,P<.0001Women:BEE(kcal/d)=655.0955+9.5634(weight)+1.8496(height)−4.6756(age)r2=0.53,F3,99=37.8,P<.0001In

Weight and Height

Body weight accounted for 75% of the explained variation in BEE (Table 2). Benedict expressed the opinion that lean body mass rather than total body weight was the quantity most predictive of BEE, and that total body weight was predictive of BEE because of strong covariance with lean body mass (2). Covariance between total body weight, lean body mass, and BEE has since been well established (14), (15), (16), (17).

Height was associated with energy expenditure independent of weight. Why height

Comments on the use of the Harris-Benedict Equations in Obese Persons

One criticism leveled at the Harris-Benedict equations is that their use with total body weight in obese persons overestimates true BEE, because a greater portion of an obese person's weight is nonrespiring adipose tissue, skewing the usual relationship between total body weight and lean body mass. Obese persons have reduced energy expenditure per kilogram total body weight, but normal energy expenditure per kilogram lean body mass (14), (15), (16). To correct for the effect of obesity on

Conclusion

The Harris-Benedict equations remain the most commonly used predictive equations for BEE. The equations were developed as normal standards against which BEE measured during disease states could be compared. The equations continue to be used in that capacity, and are also used clinically as a basis for prescribing energy intake for hospitalized patients, and to formulate dietary intake goals for weight loss.

Error is inherent in the Harris-Benedict equations. Only between 50% and 75% of the

References (26)

  • Harris JA, Benedict FG.A Biometric Study of the Basal Metabolism in Man. Washington, DC: Carnegie Institution of...
  • F.G Benedict

    Basal metabolism data on normal men and women (series II) with some considerations on the use of prediction standards

    Am J Physiol.

    (1928)
  • F.G Benedict et al.

    The physiology of extreme old age

    N Engl J Med.

    (1932)

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    Copyright © 1998 American Dietetic Association. Published by Elsevier Inc. All rights reserved.