Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  1. To identify if the frequency of consumption of particular foods, such as foods outside of Canada’s Food Guide to Healthy Eating, was greater in obese children and adolescents, compared to non-obese and whether this frequency was associated with body fat percentage.
  2. To determine if consuming food away from home (FAFH) had a negative effect on the nutritional intake of the diets of children and adolescents.  
Inclusion Criteria:
  • Adolescents ages four to 16. Obese were on a waiting list at the Children’s Exercise and Nutrition Centre
  • Obese: At or above the 95th percentile.
  • Non-obese: At or below the 75th percentile.
Exclusion Criteria:
  • Children with BMI between the 76th and 94th percentiles.
  • Children with eating disorders (dieting, genetic disorders of obesity, physical limitations, and other co-morbidities that could affect eating such as psychiatric disorders or attention deficit disorders).
Description of Study Protocol:


  • Obese group was on a one- to two-month waiting list at the Children's Exercise and Nutrition Center.
  •  Non-obese subjects were recuited from community advertisements.


  • Obtained demographic data (age, gender, income level)
  • Anthropometric measurements (height, weight, percentage of body fat by bioelectrical impedance analysis)
  • Dietary history (24-hour recall, a modified FFQ and a three-day food record).

Statistical Analysis

  • T-tests (test for differences in intake between the two groups)
  • Chi-square test (compare types of milk or milk products consumed)
  • Step-wise multiple regression analysis (percentage of body fat correlated with frequency in consumption of any particular food or food group)
  • Correlation (food eaten away from home related to each food group and the nutritional quality of the diet).
Data Collection Summary:

Dependent Variables

  • Body fat percentage (bioelectrical impedance analysis).

Independent Variables

  • Individual food group intake by 24-hour recall and three-day food records and FFQ data.
  • The FFQ was a 12-item questionnaire looking at high calorie foods (potato chips, peanut butter, cheese, regular soda pop, sugar-sweetened drinks, granola bars, baked goods, cookies, candy, chocolate, doughnuts and ice cream)
  • Fruits and vegetables were determined by three-day food records.
  • Fruit and vegetables were separated into fruit including fruit juice, vegetables and fruits and vegetables combined.

Control Variables

  • Age
  • Gender
  • SES
  • Total energy intake
  • Percentage of Recommended Nutrient Intake for age and gender
  • Fat in grams and as a percentage of Health and Welfare Canada Guidelines for age
  • Fat as a percentage of total energy
  • Sugar in grams and as a percentage of total energy
  • Intake from each good group and as a percentage of total energy.
Description of Actual Data Sample:
  • Initial N: 195
  • Attrition (final N): 181 (91 obese, 90 non-obese)
  • Age: Four to 16 years
  • Ethnicity: White
  • SES: All SES levels represented but majority were middle class ($20 000 to $49 000 Canadian).
  • Location: Canada.
Summary of Results:
  • No significant differences in age, gender or income between the two groups. Two groups were significantly different in height, weight, BMI, percent BMI and body fat percentage.
  • The obese subjects consumed significantly more total energy in kcal and as a percentage of RNI, more fat in grams and as a percentage of Health and Welfare Canada Guidelines, more fat as a percentage of energy and significantly more sugar in grams. 
  • Both obese and non-obese were low in fruit and vegetables, milk and milk products and consumed more meat than recommended. Grains were adequate in both groups. The only food groups that were significantly different were grains and meat, with the obese consuming significantly more as compared to Canada’s Food Guide to Healthy Eating. Obese consumed more potato chips, sugar-sweetened drinks and a combination of sugar-sweetened drinks and regular soda pop and ate more food away from home. Food away from home included ordering in, take out, restaurants, theme days at school and food bought at school. With regular soda pop and sugar-sweetened drinks combined, the results were only significant for the boys. The non-obese group consumed significantly more cheese.
  • There were significant positive correlations between frequency of meat and alternatives, grains, sugar-sweetened drinks and potato chips consumed with dietary energy, fat and sugar intake.
  • There were significant positive correlations between body fat percentage with meat and alternatives (R=0.39, P=0.0001), sugar-sweetened drinks (R=0.19, P=0.0001) and food away from home (R=0.16, P=0.02) and significantly negative correlations between body fat percentage with cheese (R=-0.21, P=0.003) and fruit including fruit juice (R=-0.14, P=0.05).
  • Those who ate more food away from home consumed more meat and alternatives (R=0.2, P=0.007) and grains (R=0.26, P=0.0001). Fruit, vegetables, fruit and vegetables combined and milk and milk products were not correlated with food away from home. 
  • There was no analysis of a possible association between other dairy (besides cheese) or vegetables and obesity (BMI or body fat percentage).
  • Obese subjects consumed significantly more total energy in kcal (P<0.001) and as a percentage of the Recommended Nutrient Intake for Canadians (P<0.001), more fat in grams (P<0.001) and as a percentage of Health and Welfare Canda Guidelines (P<0.001), more fat as a percentage of energy (P<0.05) and more sugar in grams (P<0.001).
Author Conclusion:

In comparison to non-obese children and adolescents, obese children and adolescents consume significantly more food away from home and sugar-sweetened drinks, which contribute to a higher calorie fat and sugar intake, which positively correlates with body fat percentage.

Funding Source:
University/Hospital: Children’s Exercise & Nutrition Centre Hamilton Health Sciences (Canada)
Reviewer Comments:


  • Large sample size.
  • Dietary histories performed by the same registered dietitian, over all seasons, with the parent and child present.


  • Computer program did not differentiate between fruit and fruit juice.
  • Analysis was not adjusted for ethnicity, education level, SES, rural or urban dwelling or gender, therefore findings may not be applicable across all sectors of the population.
  • Cross-sectional study; cannot answer question about the development or etiology of obesity.
  • Non-obese group may not have been representative of all non-obese children as individuals who respond to advertisements may be more committed to healthy lifestyles.
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) N/A
  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? Yes
  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.) Yes
  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? Yes
  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? ???
  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.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  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? 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? 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? 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? N/A
  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)? Yes
  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