EE: Thermic Effect of Feeding (2013)


Alves VG, da Rocha EE, Gonzalez MC, da Fonseca RB, Silva MH, Chiesa CA. Assessement of resting energy expenditure of obese patients: Comparison of indirect calorimetry with formulae. Clin Nutr. 2009 Jun; 28(3): 299-304.

PubMed ID: 19398250
Study Design:
Diagnostic, Validity or Reliability Study
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To compare the resting energy expenditure (REE) obtained by indirect calorimetry (IC) with that estimated by the Harris-Benedict and the Ireton-Jones equations and a fixed amount of 21kcal per kg of body weight using actual, average and adjusted weights.

Inclusion Criteria:

Overweight or obese patients admitted to the Intensive Care Unit of Clinica Sao Vicente, Rio de Janeiro Brazil, (BMI from 25 to 29.9kg/m2)

Exclusion Criteria:

Not described.

Description of Study Protocol:


Overweight or obese patients (BMI from 25 to 29.9kg/m2) were recruited from the Intensive Care unit of Clinica Sao Vicente, Rio de Janeiro, Brazil.


Diagnostic, validity or reliability study.

Blinding Used

Implied with measurements.


  • Indirect calorimetry measurements were prospectively performed in patients
  • Some patients were on mechanical ventilation
  • Some measurements were performed using the canopy in the fasting state and 24 hours after achieving calculated caloric requirements.

Statistical Analysis

  • The statistics were parametric after the determination of normal distribution for the studied variables by Kolmogorov-Smirnoff test using paired T-test and one-way ANOVA
  • The indirect calorimetry measurements were compared by concordance correlation coefficients using the Lin's test and limits of agreement by the Bland and Altman test to estimates of caloric requirements using the formulae described
  • Simple linear regression analysis was also done using the Pearson correlation coefficient with the level of significance at less than 5%
  • The software used for the statistics were Microstat II Release 2.5 and STATA software version 9.2.


Data Collection Summary:

Timing of Measurements

Each patient was measured twice in a fasted state and 24 hours after achieving calculated caloric requirements.

 Dependent Variables

  • Resting energy expenditure measured by indirect calorimetry (IC) using the Deltatrac II
    • In the fed state, measurements were performed along with the administration of enteral or parenteral nutrition
    • Each test was performed exclusively by one of two certified professionals for a minimum of 20 minutes after achieving steady state
    • A pre-established checklist was followed and verified before each measurement for the certification of its precision.
  • Resting energy expenditure (REE) estimated by the Harris Benedict and the Ireton-Jones equations and a fixed amount of 21kcal per kg of body weight, using actual, average and adjusted weights
    • Actual body weight (ABW) was obtained using a microprocessed bed scale or a precision mechanic anthropometric scale (Filizola)
    • Basal energy expenditure (BEE) was calculated using the Harris Benedict formula
    • The adjusted body weight (AjBW) was determined by the formula AjBW=(ABW – IBW) x 0.25 + IBW
    • The Ireton-Jones formula for obese patients was also used as well as the fixed amount of 21kcal per kg of actual body weight

Independent Variables

  • Critically ill, overweight and obese patients
  • Patient's height, weight, sex, age, diagnosis, body mass index, type of nutrition support and calculated caloric requirements were collected and tabulated.
Description of Actual Data Sample:
  • Initial N: 44 total (18 females, 26 males)
  • Attrition (final N): 44
  • Age: Mean age 59±18 years
  • Other relevant demographics: Mean actual body weight 104.83±32.30kg
  • Anthropometrics: Mean BMI 36.41±10.56kg/m2
  • Location: Brazil.
Summary of Results:

Key Findings

  • 42 patients had their measurements taken in the fasting state, before starting enteral or parenteral nutrition
  • 29 of them were evaluated again after achieving the estimated caloric requirements and indirect calorimetry was performed during feeding
  • The mean time between measurements for the same individuals was four days, the time needed in most cases to achieve the calculated caloric needs
  • The best REE prediction value in the fasting state was obtained with the HB equation using the actual body weight (HB/ABW), 1,873±484kcal per day (P=0.49) when compared to the REE of 1798±495kcal per day measured by IC
  • After achieving caloric needs, the best REE prediction values were using the HB/ABW equation 1,873±484kcal per day (P=0.56) and the IJ equation with the adjusted body weight, 2,103±580kcal per day (P=0.19) when compared to 1,948±507kcal per day measured by IC
  • When the above results were plotted on the Bland and Altman limits of agreement test their average bias were low, but the ranges of their absolute values from the observed average agreement were large, 531kcal or more.
Author Conclusion:

The energy expenditure of obese mechanically ventilated patients should not be estimated by formulae, despite the absolute similarity found in this study between HB/ABW formula and the IJ/AjBW formula with that measured by IC, due to large ranges of variability shown with the limits of agreement test when compared to the measured REE by IC.

Funding Source:
University/Hospital: Clinica Sao Vicente, Favea Rio de Janeiro Brazil
Reviewer Comments:

Inclusion and exclusion criteria were not well described.

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) Yes
  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) Yes
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? ???
  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? No
  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? ???
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) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  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")? Yes
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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? Yes
  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? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  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? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  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? No
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