MNT: Weight Management (2015)

Goulet J, Lapointe A, Lamarche B, Lemieux S. Effect of a nutritional intervention promoting the Mediterranean food pattern on anthropometric profile in healthy women from Quebec city metropolitan area. Eur J Clin Nutr. 2007; 61: 1,293-1,300. PubMed ID: 17299486
Study Design:
Time Study
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
  • To evaluate the long-term impact of a nutritional intervention promoting a Mediterranean food pattern on anthropometric profile in healthy, free-living women
  • To determine which of the individual components of the Mediterranean diet (MEDdiet) could explain changes in body weight and waist circumference.
Inclusion Criteria:
  • Ages 30 years to 65 years
  • Female
  • Living in Quebec city metropolitan
  • Free from metabolic disorders  requiring treatment
  • Stable body weight for at least three months before the start of study
  • Be in charge of food purchases and meal preparation most of the time
  • Signed informed consent.
Exclusion Criteria:
Consuming a diet concordant with Mediterranean food pattern.
Description of Study Protocol:


Recruited through the Laval University newspaper during the summer of 2001.


The study was conducted in two phases, with each phase conducted using a similar 12-week intervention design. The first phase started in August 2001 and the second phase began in January 2002. Intervention included two sessions with eight participants per group. The first group session included an explanation of MEDdiet principles and health benefits explained by a registered dietitian, which was then followed by a Mediterranean cooking lesson four weeks later. Individual visits with the registered dietitian took place during the first, sixth and 12th weeks of intervention in order to evaluate the dietary changes and select further objectives for increasing adherence to Mediterranean food pattern. Unannounced qualitative 24-hour recalls were performed by telephone at weeks two, four, eight and 10. At 12 weeks after the end of nutritional intervention, subjects were invited to a last individual session with a dietitian to complete food frequency questionnaire. Three registered dietitians were trained to provide a standardized intervention. 


Education on the Mediterranean diet was provided by a registered dietitian.

Statistical Analysis

  • Data collected at beginning and after six, 12 and 24 weeks were compared using analysis of variance for repeated measures 
  • In the presence of significant time effects, contrast analyses were used to determine precisely the location of significant differences
  • Dietary variables were log-transformed when necessary to obtain normal distribution
  • Spearman correlations computed to quantify associations among variables
  • P<0.05 is statistically significant.


Data Collection Summary:

Timing of Measurements

  • Validated administered food frequency questionnaire (FFQ) completed at screening and at weeks six, 12 and 24
  • Three-day food records were completed at baseline and week twelve 
  • Body weight, waist circumference and height were measured and BMI was calculated at weeks zero, six, 12 and 24
  • Evaluation of nutrient intake derived from FFQ was performed using the Nutrition Data System for Research software version 4.03 and completed at week zero, 12 and 24
  • The Mediterranean dietary score (MedScore) was calculated using FFQ (score zero to 44, with a higher score indicating closer adherence to Mediterranean diet).

Dependent Variables

  • Anthropometric profile (weight, waist circumference and BMI)
  • MedScore
  • Dietary intake.

Independent Variables

Nutritional intervention by registered dietitian.

Control Variables

Description of Actual Data Sample:
  • Initial N: 77 females
  • Attrition (final N): 62 females
  • Age: 46.7±7.7 years.
  • Baseline weight: 67.3±12.3kg
  • Baseline BMI: 25.7±4kg/m2
  • Waist circumference: 82.9±11.1cm.


Quebec City, Canada.

Summary of Results:

Key Findings

  • BMI decreased slightly but significantly after the beginning of nutritional intervention slightly after six weeks (P=0.05). Reduction remained statistically significant at week 12 but not at week 24.
  • Waist circumference measured at week 12 was statistically lower than value at baseline (P<0.0001) and this remained significant at week 24 (P=0.04)
  • MedScore increased significantly after 12 weeks of nutritional intervention (from 21.3±3.5 to 29.2±4.5 arbitrary units) and increased in the consumption of olive oil, vegetables, fruits, legumes, nuts and seeds, grains, poultry and fish was observed and reflected by a significant increase of the partial MedScore for these components (P<0.01) and reduction of red meat and processed meat and sweets was observed (P<0.0001)
  • At week 24, MedScore was significantly decreased compared to the value measured at week 12 (P<0.0001) but remained significantly higher than values at baseline and consumption of olive oil, legumes, nuts and seeds and fish decreased and the consumption of sweets increased significantly between week 12 and 24 (P<0.05).
Variables Week Zero Week Six Week 12 Week 24
MedScore (arbitrary unit) 21.3±3.5 29±4.4a 29.2±4.5a 26±4.9a, b
Weight (kg) 67.3±12.3 66.9±12.2c 66.8±121.8c 67.7±11.7d
BMI (kg/m2) 25.7±4 25.6±4c 25.5±3.8c 25.8±3.9d
Waist circumference (cm) 82.9±11.1 82.7±10.7 81.7±10.3a 82.6±10.9c, d

Significantly different from week zero: cP<0.05; aP<0.0001.

Significantly different from week 12: dP<0.05; bP<0.0001.

Variables Week Zero Week 12 Week 24
Energy (kcal) 2,084±491 1,954±422a 1,953±350b
Proteins (percentage) 15.7±2.7 17.1±2.1c 17.3±2.1c
Lipids (percentage) 36.3±6.2 33.5±5.4b 33.6±5.5b
SFA (percentage) 12.3±3 9.4±1.9c 9.7±1.9c, d
MUFA (percentage) 15.7±2.7 15.4±3.4 15±3.2
PUFA (percentage) 5.6±1.5 6.3±1.4b 6.3±1.4b
Transfats (percentage) 1.4±0.4 0.9±0.3c 1.1±0.3c
Carbohydrates (percentage) 46.4±6.1 48.8±5.4b 47.5±5.8c,d 
Total dietary fiber (g) 19.5±4.9 25±6.5c 23.7±5.6c, d
Alcohol (percentage) 3.6±3.2 3.3±2.9 4±3.2

Significantly different from week zero: aP<0.05;  bP<0.01; cP<0.0001.

Significantly different from week 12: dP<0.05.


Author Conclusion:
Nutritional intervention promoting a Mediterranean food pattern in free-living conditions was effective in modifying food habits of healthy women from Quebec City metropolitan area. Significant improvements in the anthropometric profile were observed. Results suggest that a Mediterranean food pattern is not associated with weight gain.
Funding Source:
Government: Canada Research Chair in Nutrition, Functional Foods and Cardiovascular Health
Reviewer Comments:
Strength: Intent-to-treat analysis
Limitation: FFQ may not accurately portray individual caloric intake changes.
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? 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? 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? 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? 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? No
  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.) No
  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? Yes
  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? 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? No
  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)? Yes
  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? N/A
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