EE: Thermic Effect of Food (2014)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To examine the effect on thermic effect of food (TEF) of 2 factors:

  1. Meal composition: high-carbohydrate-low fat (HCLF) and low-carbohydrate-high-fat (LCHF)
  2. Energy content of the ingested meal: 2520 kJ (600 kcal) and 5040 kJ (1200 kcal).


  • Steady state: Not addressed
  • Post-prandial Metabolic Rate (PPMR): Mean values over 6 hrs
  • BMR: Use of term BMR in these publications matches projects definition of RMR, will use RMR in evidence summary.
Inclusion Criteria:
  1. Understand and give written consent
  2. Healthy non-obese women,
  3. Take no medication at the time of study.
Exclusion Criteria:
  1. Refusal to consent
  2. Not meeting inclusion criteria
Description of Study Protocol:

Each subjects consumed four different test meals on separate occasions. The order of the presentation of the meals was randomized.

Assessment of BMR was performed before and after meal.


  • Ht, Wt, BMI, body fat, fat free mass (FFM)


  • Monitored heart rate? No
  • Body temperature? No
  • Medications administered? No

Resting energy expenditure

  • IC type: Open circuit IC using Douglas bag techniques
  • Equipment of Calibration: Yes, using standard gas mixtures
  • Coefficient of variation using std gases: No
  • Rest before measure (state length of time rested if available): 30 min
  • Measurement length: Baseline: 2 10-min; after intervention: 3 10-min and 5 20-min assessments
  • Steady state: Not addressed
  • Fasting length: Overnight
  • Exercise restrictions XX hr prior to test? No
  • Room temp: 18°C
  • No. of measures within the measurement period: After intervention 8 measures in 300 min
  • Were some measures eliminated? No
  • Were a set of measurements averaged? Yes ( 2 10-min were average for RMR baseline)
  • Coefficient of variation in subjects’ measures? Yes
  • Training of measurer? Not addressed
  • Subject training of measuring process? Not addressed


HCLF (meal A: 600kcal; meal C: 1200 kcal)

70% CHO

19% fat

11% PRO

LCHF (meal B: 600kcal; meal D: 1200 kcal)

24% CHO

65% fat

11% PRO

Data Collection Summary:

Outcome(s) and other measures

  1. Basal metabolic rate
  2. 5 h thermic effect of food (TEF)

Blinding used: No

Description of Actual Data Sample:
  • 16 healthy non-obese females aged 22±1.5, range 18-40 y.

Statistical tests

  • 2x2 factorial analysis of variance
  • Student’s paired T-test.
Summary of Results:

Descriptive (Mean±SE)

Brit J Nutr (5-hr measures), Total: 16 Females


Age, y


Wt, kg


BMI, kg/m2


Fat-free body mass


BMR, kcal/min


Thermic Effect of Food (TEF); n=16

  • On average, baseline mean RMR value before subjects consumed a High CHO, Low Fat 600 kcal meal was 0.88±0.01 (SE) kcal/min and before one 1200 kcal High CHO, Low Fat meal was 0.88±0.1 kcal/min (SE)
  • The thermic effect of food over 5 hours was 54±3 (SE) and 85±5 (SE) after consuming a small 600 and large 1200 High CHO, Low Fat meals, respectively.
  • The mean RMR value before subjects consumed a 600 kcal Low CHO, High Fat meal was 0.87±0.01 kcal/min(SE) and before one large 1200 kcal Low CHO, High Fat meal 0.83±0.1 (SE).
  • The thermic effect of food over 5 hours was 54±2 and 81±4 kcals±SE after consuming a small 600 and large 1200 High CHO, Low Fat meals, respectively.


  • The 5-h TEF values expressed as % of ingested energy were 9.0±0.5% and 9.0±0.6% for one 600 kcal High CHO, Low Fat and Low CHO, High Fat meals, respectively.
  • The 5-h TEF values expressed as % of ingested energy were 7.0±0.4% and 7.0±0.3% for one 1200 kcal High CHO, Low Fat and Low CHO, High Fat meals, respectively
  • No significant differences were observed between either the two feeding regimens or between the two meal compositions (P>0.05).

Subject variability

  • From 5-h TEF publication: There was significant inter-subject variability in TEF values (P<0.001; CV 18.6%-24.6%)
Author Conclusion:
  • “The present study did not establish any relationship between meal composition and TEF. There were no significant differences in the 5h TEF values between HCLF and LCHF meals.”
  • “At both levels, meal composition did not have any significant effect on TEF.”
  • “Meals of high energy content had TEF values significantly greater than those of low energy content.”
  • “The 5-h TEF values obtained in the present study were 21 and 33% above the baseline RMR for the 600 kcal and 1200 kcal meals respectively.”

[Analyst note: using 600 and 1200 kcal BMR kcal/min means this approximately represents increases of 266 and 288 kcal/d above baseline premeal levels)]

  • “The reasons for the variations in inter-subject variability are unclear. However, it may be speculated that this variation could be due to inherent differences with regard to efficiency in digestion, absorption and disposition of nutrients in the body.”
Funding Source:
University/Hospital: Sokoine University of Agriculture
Reviewer Comments:


  • Inter-subject variability was assessed.
  • Randomization of the sequence of the test meals was performed.
  • Measurement protocol was described in detail.


  • Generalizable only to healthy women.
  • Physical activities, menstrual cycles were not considered in the analysis.
  • Limitations were not discussed.
  • While the subjects studied are most likely represented in both data sets, the Br J Nutr article reports TEF for 5 hr in 16 subjects.
  • The research design is a repeated measures crossover study so that 16 individuals are represented in each group.
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? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
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? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? N/A
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")? N/A
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? N/A
  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? N/A
  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? N/A
5. Was blinding used to prevent introduction of bias? No
  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.) N/A
  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? N/A
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? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  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? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? N/A
  7.7. Were the measurements conducted consistently across groups? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  8.3. Were statistics reported with levels of significance and/or confidence intervals? N/A
  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)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? No
  9.1. Is there a discussion of findings? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A