Adult Weight Management

Healthy Non-Obese Adults (2010-2012)

Citation:

Livingston EH, Kohlstadt I. Simplified resting metabolic rate - predicting formulas for normal-sized and obese individuals. Obes Res. 2005; 13 (7): 1,255-1,262.

PubMed ID: 16076996
 
Study Design:
Diagnostic, Validity or Reliability Study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

The study tested whether resting metabolic rate (RMR) can be predicted from an allometric formula with weight alone as an independent variable.

Inclusion Criteria:
  • Complete medical evaluation showing that patients were free of significant disease that potentially could alter RMR measurements
  • Metabolic panel showing that the patients did not have thyroid conditions
  • Chest X-ray and medical exam verifying that respiratory illness was not present.
Exclusion Criteria:

Patients taking medications were not excluded, although if a patient was on a medication known to alter RMR, the test was not performed.

Description of Study Protocol:
  • Recruitment: Patients were recruited from a university-based weight-management program involving a physician-supervised very-low-calorie diet
  • Design: Diagnostic, validity or reliability study
  • Blinding used: Implied with measurements.

Statistical Analysis

  • The weight-RMR relationship was assessed by non-linear regression with the allometric power formula: RMR=a x weightb
  • Non-linear regression was performed with the SigmaPlot Graphing package (SPSS, Chicago, IL)
  • For assessment of the effect age had on RMR prediction, a second equation was solved: RMR=a x weightb + (C x age).
  • RMR prediction with the Harris-Benedict type of formula follows the general form of: RMR=constant + A1 Weight + A2Height + A3Age, where constant A1, A2 and A3 were solved by multiple regression using the SAS program
  • Significance of the fitted coefficients was assumed when P<0.05
  • The proportion of RMR variance accounted for each coefficient by semi-partial correlation analysis using type II sum of squares.
Data Collection Summary:

Timing of Measurements

All measurements made at the same time.

 Dependent Variables

  • Resting metabolic rate was measured as part of a comprehensive medical evaluation for patients participating in a university-based weight-management program involving a physician-supervised very-low-calorie diet. RMR was measured by indirect calorimetry using a Beckman Metabolic Cart. One of two certified exercise physiologists in a standardized room measured subjects.
  • The test was conducted twice with the higher of the two RMRs selected for the analysis
  • RMR was predicted by the James, allometric and Harris-Benedict formulas.

Independent Variables

  • Weight
  • Height
  • Age.
Description of Actual Data Sample:
  • Initial N: 356 measured women and 299 measured men
  • Attrition (final N): 356 measured women and 299 measured men
  • Age: Women mean age, 39±13 years; men mean age, 36±15 years
  • Ethnicity: Not described
  • Other relevant demographics: Not reported
  • Anthropometrics: Mean weight for women, 90±37kg; mean weight for men, 96±45kg
  • Location: Not reported, data secured from Harris-Benedict and Owen databases.
Summary of Results:

Key Findings

  • Power law modeling of the RMR-body weight relationship yielded the following RMR-predicting equations:
    • RMR women: 248 x weight0.4536 - (5.09 x age)
    • RMR men: 293 x weight0.4330 - (5.92 x age).
  • Partial correlation analysis revealed that age significantly contributed to RMR variance and was necessary to include in RMR prediction formulas
  • The James, allometric and Harris-Benedict formulas all yielded reasonable RMR predictions for normal-sized and obese subjects.
Author Conclusion:
  • A simple power formula relating RMR to body weight can be a reasonable RMR estimator for normal-sized and obese individuals, but still requires an age term and separate formulas for men and women for the best possible RMR estimates
  • The apparent performance of RMR-predicting formulas is highly dependent on the methodology employed to compare the various formulas.
Funding Source:
Other: Hudsen-Penn Endowment Fund
Reviewer Comments:

Questionable validity of the Beckman Metabolic Cart.

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? No
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? Yes
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? Yes
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? Yes
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? Yes
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes