EAL

NNNS: Appetite (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine the effects of familiar carbonated soft drinks sweetened with aspartame on subjective hunger, energy intake and macronutrient selection at a lunchtime meal.

Inclusion Criteria:

Complete restrained eaters test and food liking checklist and food acceptability list
Males 19 to 25 years of age with BMI ranging from 22 to 29.

Exclusion Criteria:

Smoked
Followed a vegetarian diet
Diagnosis of phenylketonuria
Food allergy
Major medical illness
Received medications.

Description of Study Protocol:

Recruitment

Recruited by posters placed throughout the University of Toronto and by word of mouth. Subjects gave informed consent, approved by the University of Toronto Human Subjects Review Committee.

Design

Previous night fast.
Consumed breakfast at lab within 30 minutes.
Breakfast was tailored to subjects' weight, so it provided 25% of average energy expenditure.
Adjusted by amount of cereal and milk presented.
Measures of appetite and food preference were taken throughout the morning.
Treatment randomized across subjects.
Pre-determined soft drinks were consumed.
Buffet lunch served, subjects were instructred to eat until comfortably full and were allowed 30 minutes to finish lunch.
Macronutrient content was the same across lunches.
The buffet lunch was the same at each test session.
Four treatments of carbonated beverages included 280ml of mineral water, one can of a soft drink (280ml) consumed in either two or 10 minutes or two cans of a soft drink (560ml), consumed in 10 minutes, administered at 11:00 a.m.

Blinding Used

Subjects unaware of the nature of the soft drink.

Statistical Analysis

Overall ANOVA.

Data Collection Summary:

Dependent Variables

Food intake and selection: Food consumed at the end of lunch was measured and total calories were calculated. Macronutrient composition was determined by chemical analysis and food composition tables.
Visual analogue scales: Made throughout the morning.

Control Variables

Weight and height were measured at recruitment.

Description of Actual Data Sample:

Initial N: 20 male subjects
Attrition (final N): No drop-outs
Age: 19 to 25 years
Anthropometrics: BMI from 22 to 29
Location: Department of Nutritional Sciences, University of Toronto.

Summary of Results:

Food Intake and Selection

Macronutrients were not consumed in equal amounts (P<0.001). Post hoc analyses showed that subjects ate more fat than CHO or protein (P<0.05, P<0.01, respectively) and more CHO than protein (P<0.05).

Subjective Appetite

Treatment had a significant effect on both desire to eat (P<0.005) and fullness (P<0.001).
Consumption of two soft drinks (560ml, 320-340mg aspartame) significantly reduced subjective hunger from 11:05 to 11:30 a.m., compared to one soft drink (280ml, 160-170mg aspartame) or 280ml of mineral water.

Food Appeal

Treatment had no effect on food appeal measured by Visual Analogue Scales (VAS).

Restrained Eaters

Restrained eaters weighed slightly more than non-restrained eaters (78±4.1kg vs. 70±2.6kg, mean and SEM).
Restrained and non-restrained eaters consumed significantly different amounts of food at the lunchtime meal.
Restrained eaters consumed more in all treatment conditions and for all macronutrients.
No differences on any of the 'motivation to eat' questions, though restrained eaters found protein foods and low-calorie foods less appealing than did non-restrained eaters.

Beverage Consumption Checklist

Everyday soda consumption ranged from zero to four 280ml cans per day, with a mode of zero and a median of one.
Of those that regularly consumed pop, six in ten drank regular soda, one drank diet soda and the remaining three drank equal amounts of both. Only three of the 20 subjects identified the flavored (aspartame) beverage as diet soda, none of these being diet soda drinkers.

Author Conclusion:

Consumption of aspartame-sweetened beverages did not increase short-term subjective hunger or food intake, in a meal taken within the following 60 to 90 minutes.
These results support the growing evidence that consumption of foods and beverages containing non-nutritive sweeteners do not increase hunger and food intake.

Funding Source:

University/Hospital:

University of Toronto (Canada)

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

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?		Yes
	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?	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%.)	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?		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?	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?	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)?	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?	No
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