EE: Thermic Effect of Food (2014)


Raben A, Agerholm, Larsen L, Flint A, Holst JJ, Astrup A. Meals with similar densities but rich in protein, fat, carbohydrate or alcohol have different effects on energy expenditure and substrate metabolism but not on appetite and energy intake. Am J Clin Nutr. 2003; 77(1): 91-100.

Study Design:
Randomized Crossover Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To investigate the effects on appetite, energy intake and expenditure, and substrate metabolism of meals rich in one of the four macronutrients.


  • Steady state: Not defined; however, unlikely due to post-prandial measurement, subjects were allowed to watch light entertainment movies
  • DIT (kcal): Area under the EE curve above and below fasting level (kcal per minute * minute)
  • DIT (percent): 100 time DIT [kJ per energy in test meal (kJ)].


  • The rate of protein oxidation was assumed to be constant throughout the test day. One gram nitrogen was assumed to correspond to 6.25g protein, and approximately 81% of the ingested nitrogen was assumed to be excreted in the urine
  • Alcohol was assumed to be totally oxidized during the five-hour post-prandial measurements and its oxidation rate was estimated to be constant with 1.89kJ per minute for women and 2.26kJ per minute for men.
Inclusion Criteria:
  • Understand and give written consent
  • Aged 20 to 30 years
  • Normal weight
  • BMI greater than 18.5 but less than 25.5
  • Non-smoker
  • Not an elite athlete
  • Normal alcohol habits
  • No history of obesity, diabetes mellitus or liver disease
  • Normal BP
  • No regular use of medication (except for birth control pills).
Exclusion Criteria:
  • Refusal to consent
  • Not meeting inclusion criteria.
Description of Study Protocol:

A cross-over design in which baseline and post-prandial variables were measured over a period of five hours after consumption of the four test meals. The test meals were given in random order to the subjects on separate days.


  • Height
  • Weight
  • BMI
  • Fat mass percent.


  • Monitored heart rate? Not specified
  • Body temperature? Not specified
  • Medications administered? No.

Resting Energy Expenditure

  • IC type: Not specified
  • Equipment of calibration: Not specified
  • Coefficient of variation using std gases: Not specified
  • Rest before measure (state length of time rested if available): Yes, 30 minutes
  • Measurement length: 45 minutes before meal, 15 to 315 minutes continuous measurements after meal
  • Measurement duration: 300 minutes
  • Steady state: Not specified if steady state has to be reached
  • Fasting length: 10 hours (overnight)
  • Exercise restrictions XX hour prior to test? Two days before each test day
  • Room temp: Not specified
  • Number of measures within the measurement period: Not specified
  • Were some measures eliminated? No
  • Were a set of measurements averaged? No
  • Coefficient of variation in subjects’ measures? No
  • Training of measurer? Not specified
  • Subject training of measuring process? Not specified.


The day before each test day, subjects were given an individual standardized, weight maintenance, carbohydrate-rich diet for one day.

  • PRO: 13.2% of kcal
  • CHO: 49.2% of kcal
  • Fat: 37.4% of kcal
  • Alcohol: 0
  • Energy density: 8.5kJ per g
  • Dietary fiber: 1.7g per mJ
  • Four-test meal: Energy density 4.8kJ per g, dietary fiber 1.8g per mJ (2,500kJ for women and 3,000kJ for men).

Protein Meal

  • PRO: 31.8% of kcal
  • CHO: 37.2% of kcal
  • Fat: 31.1% of kcal
  • Alcohol: 0.

Carbohydrate Meal

  • PRO: 12.2% of kcal
  • CHO: 65.4% of kcal
  • Fat: 23.7% of kcal
  • Alcohol: 0.

Fat Meal

  • PRO: 11.6% of kcal
  • CHO: 23.9% of kcal
  • Fat: 64.6% of kcal
  • Alcohol: 0.

Alcohol Meal

  • PRO: 12.1% of kcal
  • CHO: 42.9% of kcal
  • Fat: 24.3% of kcal
  • Alcohol: 23.0% of kcal.

Intervening factor: The women were screened for menstrual cycle, and during the study of the four separate test days were placed at the same time of the women’s cycle so that the hormone fluctuations would not affect the measurements.

Data Collection Summary:

Outcome(s) and Other Measures

  • Energy expenditure (EE) and oxidation rate of protein, carbohydrate, fat and alcohol were calculated from the gas exchange and urinary nitrogen measurements
  • Diet induced thermogenesis (DIT)
  • Blood test:
    • Glucose
    • Lactate
    • Insulin
    • Glucagons
    • Triacylglycerol
    • Non-esterified fatty acids
    • Leptin.
  • Satiety score, ad libitum energy intake, appetite sensation.
Description of Actual Data Sample:
  • N=19 (nine women, 10 men)
  • Age 23.3±0.5.

Statistical Tests

  • All means were given as means±SEM
  • Response curves after the four test meals were compared by ANOVA.
Summary of Results:


  Men (N=10) Women (N=9)
Weight, kg 75.7±2.6 60.9±1.6
Height, m 1.82±0.2 1.69±0.02
BMI 22.9±4.0 21.3±0.5
Fat mass, percent 15.0±1.1 22.1±1.1

Satiety Scores (Energy Intake)

There were no significant differences in hunger or satiety sensations or in ad libitum energy intake after the four meals.

Energy Expenditure and DIT

  • Post-prandial EE was initially higher after the alcohol intake, but at the end, EE was highest for the protein meal (meal x time effect: P<0.001)
  • Average DIT was 17% higher after the PRO meal (not significant) and 27% higher after the alcohol meal (P<0.01) than after the CHO and fat meals (meal effect: P<0.01)
  • When expressed as a percentage of energy intake, DIT averaged 8.3% after the PRO meal, 9.0% after the alcohol meal, and 7.1% after both the fat and CHO meals (meal effect: P<0.01).
  • Group mean diet-induced thermogenesis (i.e., area under the EE curve above and below the fasting level or kcal per minute x minute) was 50kcal per minute for protein meal, 43kcal per minute for CHO and Fat meals and 54kcal per minute for alcohol meal.
  • There were no sex or sex x meal effects on EE or DIT.
  • After the alcohol meal, fat oxidation and leptin concentrations were greatly suppressed (meal effect, P<0.001 and P<0.05) and triacylglycerol concentrations were as high as after the fat meal.

[Analyst note: Figure 3, Energy expenditure inset was attempted to interpret energy expenditure increases related to diet-induced thermogenesis; However, y-axis (dependent variable) was very condensed and increasing large errors in interpretations. They have not been abstracted.]

Measurement Process

  • Number of measurements: Continuous measurements
  • Length of measurements: Baseline 45 minutes (15 to 315 minutes after consumption of test meals).

Measurement Timing

  • Sleep or rest: Rest
  • Physical activity: Minimum, sedentary
  • Food intake: Controlled
  • Various times in the day: Morning, 8:45 a.m. to 9:30 a.m.
Author Conclusion:
  • A clear finding in the present study was a 27% larger DIT after the alcohol meal than after the carbohydrate and fat meals. DIT was also larger after protein meal by 17%, but this was not significantly different from the other meals.
  • The lack of a larger DIT after the protein meal, as was expected from previous suggestions and short-term studies, may related to the use of a more stringent post-hoc test (Turkey’s) in the present than in the previous studies or the use of more compound meals instead of a single macronutrient
  • The DIT remained increased after the alcohol and protein meals at the end of the five-hour measurement period suggest that the effects of these meals might have been more pronounced had our measurement period been longer
  • On the basis of present five-hour results, our oxidation hierarchy can be summarized as follows: alcohol is greater than protein equals fat equals carbohydrate.
Funding Source:
Government: Danish Research Council
Reviewer Comments:


  • Cross-over design; randomization of tests was done; chances of systematic measurement error were greatly reduced
  • Controlled for other intervening factors, including physical activity, diet, weight, gender
  • Appropriate statistical analysis
  • Study design answers the research questions.


  • Applied to healthy young adults
  • Don’t know the magnitude of the effects of the four different diets over energy expenditure after five hours
  • Limitations of the study were not fully discussed
  • IC measurement protocol did not define steady state; post-prandial measures were taken while subjects watched light entertainment movies. Therefore, steady state, as defined by the project, was not achieved.
  • Based on the present study, restriction of alcohol intake of at least more than five hours prior to energy measurements may be recommended.
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? N/A
  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? Yes
  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? No
  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? Yes
  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