EAL

NNNS: Appetite (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

Relative contributions of the sweet taste, chemical composition and energy value of sweeteners to hunger and food intake
To further explore hunger and food intake in free-living individuals consuming self-selected diets along with a prescribed aspartame- or sucrose-sweetened food.
To monitor both short- and long-term dietary responses to ingestion of aspartame and sucrose.
Monitor the percentage of calories derived from predominantly sweet, sour, salty and bitter foods, following ingestion of aspartame, sucrose or a non-sweetened vehicle
To gain knowledge of the effect of sweetener use on ingestive behavior.

Inclusion Criteria:

Body weights had been stable for at least the last six months
Not adhering to any special diet
Healthy, normal weight
Minimum of four years of university education.

Exclusion Criteria:

Eating disorder determined from the Three-Factor Eating Questionnaire

Description of Study Protocol:

Recruitment: Not described
Design: Monitoring the reported hunger and food intake of a single group of healthy normal-weight individuals during a baseline week and three five-day periods, when breakfasts containing equicaloric sweetened or unsweetened cereals were provided.
Blinding used: Half of the subjects were informed as to the type of sweetener used and the other half were not.
Intervention: No intervention during Week One, but during Weeks Two, Three and Four, subjects were provided with a breakfast (70g corn flake cereal, 240ml 2% milk and 115ml orange juice) providing 445kcal. One version was unsweetened, the second coated with primarily sucrose, the third with aspartame.
Statistical Analysis: Significant at the 5% level of probability, dietary records analyzed with Nutritionist III, dependent variables (hunger ratings, meal and snack, total intake) by ANOVA and T-tests.

Data Collection Summary:

Diet records: Kept during baseline for seven days and during weekdays in Weeks Two through Four. Intake was not monitored over the weekend. Subjects were not instructed to alter their customary diet in any way except that during the latter three weeks of the study, the experimental breakfast was to be consumed each day before any other food or beverage. Subjects received one of each of the three cereals for five consecutive days.
Dietary habits: Recorded on the first day of the study.
Three-factor eating qustionnaire: Completed on the final test day.
Hourly hunger questionnaire: Ratings were made every day diet records were kept. Subjects were provided with a pocket timer, which alerted them for hourly ratings. Subjects recorded level of hunger on a nine-point category scale.

Description of Actual Data Sample:

Initial N: 24 adults (12 male and 12 female)
Attrition: No drop outs
Age: 28.2±1.9
Anthropometrics: BMI 22.2±0.5.

Summary of Results:

Hunger

Declined following each meal.
Hunger was lower following the meal with aspartame-sweetened cereal, relative to the other two hours following a meal.
There was no evidence of a long-term effect of sweetener type.

Analysis of intake at participant defined eating occasions

Lunch and dinner meals were significantly larger following the aspartame cereal than either the plain or sucrose-sweetened cereal.
Total daily energy intake did not differ between experimental weeks, although there was a trend for higher intakes following aspartame use. The trend for higher use was mainly due to knowledge effect: Informed subjects ingested, on average, 224kcal per day more during the aspartame week vs. sucrose week and 95kcal more than the plain cereal week.

Total daily energy intake

Did not differ between experimental weeks, athough there was a trend for higher intakes following aspartame use.

Sensory data

There was a significant taste quality effect (P<0.001), where a higher percentage of calories was derived from sweet and salty foods than sour and bitter items. However, this did not show any significant effect of cereal on the calories derived from the four taste qualities.
Subjects ingested significantly fewer bitter calories on days when sucrose-sweetened cereal was ingested, relative to the unsweetened cereal (2.5% vs. 7.0% of total calories).

Relationship between hunger and energy intake

No significant observation for any period.

Author Conclusion:

Neither sweet taste nor aspartame alone significantly affected reported hunger, daily energy intake nor subsequent selection of foods with varying taste qualitites.
There was a trend for higher intakes following aspartame use, especially for those subjects who had been informed of sweetener type.
The study failed to find an appetite-stimulating effect in either sweetness or sweetener (aspartame or sucrose).

Limitations

Discrepancies in findings between the literature may be due to differences in vehicles used to carry the sweeteners or other methodologcial differences.

Funding Source:

Industry:

Ralston-Purina Company, WaWa Dairies

Food Company:

Commodity Group:

Not-for-profit

Foundation associated with industry:

In-Kind support reported by Industry:

Yes

Reviewer Comments:

Discrepancies in results and discussion section.

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?	No
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)	No
	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?	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%.)	N/A
	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?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	Yes
	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.)	Yes
	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?	No
	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?	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?	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?	No
	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