EAL

AWM: Nutrition Education (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To investigate how fat content labels influence consumption in obese/overweight people as compared to lean people.

Inclusion Criteria:

None specifically mentioned.

Exclusion Criteria:

Excluded for taking thyroid medication.

Description of Study Protocol:

Recruitment

Not described.

Design

Nonrandomized Clinical Trial.

Blinding used (if applicable)

Not used.

Intervention (if applicable)

Participants tasted 2 isocaloric milkshakes in a staged taste test on 2 occasions, once labeled high-fat, the other labeled low-fat.

Statistical Analysis

All data analyzed in a 2 (label: high-fat vs label low-fat) x 2 (order: session 1 label high-fat vs session 1 label low-fat) x 2 (group: overweight/obese vs lean) ANOVA, with repeated measures on the first factor. Order of labels about fat content was counterbalanced over participants. The main dependent variables were the amount of milkshake consumed during the taste test, the intention to consume the milkshakes in the future, and the palatability rating.

Data Collection Summary:

Timing of Measurements

2 isocaloric milkshakes prepared each morning. Participants came to laboratory twice and milkshakes were presented in each session, told that the 2 milkshakes were extra-creamy (40% fat) or low-fat (3% fat).

Dependent Variables

Food Action Rating Scale measured future consumption
Questionnaire about sweetness, palatability, etc on 9-point scales
Restraint Scale
Eating Disorder Examination Questionnaire

Independent Variables

Milkshake consumption. Participants asked not to consume food within 2 hours prior to test. Three participants were not compliant and ate food more than 1 hour prior.

Control Variables

Description of Actual Data Sample:

Initial N: 52 subjects

Attrition (final N): 23 overweight/obese and 21 lean women. 1 person could not be weighed on scale due to size, one did not want to be weighed and BMI based on self-report. 8 participants were excluded because they realized real purpose of study, did not show for second session, or took thyroid medication.

Age: Overweight/obese: 34.0 +/- 9.0 years, lean: 33.9 +/- 8.5 years

Ethnicity: Not mentioned.

Other relevant demographics: Overweight/obese BMI: 32.6 +/- 5.4, range 25.9 - 47.9, lean BMI: 21.3 +/- 1.8, range 18.4 - 24.7

Anthropometrics: Overweight/obese group scored higher than lean group on Restraint Scale and Eating Disorder Examination Questionnaire.

Location: Netherlands

Summary of Results:

Other Findings

Label effect was in the expected direction of less (estimated future) consumption in the high-fat label condition, but was not significant for current consumption and not different between overweight/obese and lean groups.

When milkshakes were labeled high-fat in the first session, participants consumed significantly more of the milkshake labeled low-fat than of the milkshake labeled high-fat, F (1,21) = 19.62, p < 0.001.

When milkshakes were labeled low-fat in the first session, participants consumed significantly more of the milkshake labeled high-fat than of the milkshake labeled low-fat, F (1,19) = 4.47, p < 0.05.

The label did not significantly influence the palatability ratings.

Author Conclusion:

In sum, the current results suggest that effects of novelty and fat content label effects may operate together in determining consumption. The effects of novelty may even be stronger than effects of fat content labels in this kind of experiment. For the expected future consumption only the fat content label played a role, in that lower ratings were given to the milkshakes labeled high-fat, independent of familiarity with the lab situation.

Funding Source:

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

2 participant weights not accurate and 3 were not compliant with food restriction prior to test. Authors note that power may have been a problem.

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?	???
	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?		???
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	???
	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?	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?	???
	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?	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?	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?		???
	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?	No
	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