NNNS: Effect on Energy Balance (Weight) (2010)
Citation:
Kanders BS et al, An evaluation of the effect of aspartame on Weight Loss. Appetite, 1988; 11, supplement 73-84.
PubMed ID: 3190220
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:

Research Purpose:
Study designed to determine whether the addition of aspartame-sweetened foods and beverages to a prescribed, medically supervised hypocaloric weight loss program aids compliance and results in greater weight loss in a free-living population.
Inclusion Criteria:
- Consumption of aspartame products or non-aspartame products
- Willing to participate in a 12-week weight loss program with a one-year follow-up
- Overweight or obese according to the 1959 Metropolitan Life Insurance Tables.
Exclusion Criteria:
- Failure to appear for a screening appointment
- Failure to adhere to the screening protocol (i.e., unable to keep food records)
- Serious or uncontrolled disease (i.e., uncontrolled blood pressure or diabetes).
Description of Study Protocol:
Recruitment
- 86 volunteers were screened, of which 59 enrolled. Accrual began in December 1986 and was completed in March and April 1987.
Design
- Participants were randomly assigned to control or experimental diets in a prospective parallel design.
Intervention
- After a two-week screening, subjects did a three-week run-in period and were instructed to follow the BDD and to avoid all aspartame or saccharin sweetened foods and beverages. Compliance was verified through food records and subjects had to lose a minimum of six lbs during the first three weeks to be randomized into the study.
- Randomized into BDD (a continuation of run-in) or the BDD-plus-aspartame-sweetened foods and beverages. Also received behavior modification and group support each week and a prescribed walking program (15 to 30 minutes) three times a week.
- Experimental group with aspartame received milk exchanges as aspartame-sweetened pudding or milk shake and consumed at least two daily. As well as encouraged to use low-calorie table sweetener, aspartame, diet sodas and gelatin, as desired.
Statistical Analysis
- No P-values were included because the study was a pilot to test the feasibility of subject recrutiment and acceptance of the two diets. Sample size was not based on power considerations to detect a clinical difference.
Data Collection Summary:
- Dietary Intervention Control Diet: Balanced deficit diet (BDD) consisting of 1,000kcal for females and 1,200kcal for males (Table One)
- Experimental Group: Same isocaloric BDD, but additionally supplemented diets with low-calorie foods and beverages sweetened with aspartame. Minimum of two low-calorie foods daily and encouraged to select more as desired.
- Data collected at baseline and Weeks Three, Seven and 12, during active weight loss
- Body Weight: Measured on small digital spring scale
- Blood Pressure: Measured after subjects sat quietly for five minutes
- Body Composition: Assessed by electrical impedance plethysmography at baseline and Week 12
- Three-day dietary diaries: Collected to assess current sweetener use and compliance with diet. Completed at baseline and Week 12.
- Quality of Life Questionnaire: Self-adminstered; comprised of 17 statements evaluating psychologiccal, social, medical and physical well-being (Table Two)
- Changes in health status: Monitored intercurrent health events and changes in vital signs.
Description of Actual Data Sample:
- Initial N: 59 (13 males, 46 females)
- Attrition: 55 completed and included in final analyses, four excluded due to one not meeting the six-pound run-in weight, two who were randomized did not attend the seventh visit and one control dropped out before Week 12.
- Age: 20 to 60 years
- Anthropometrics: 130 to 225% of ideal body weight.
Summary of Results:
- Aspartame consumption: Mean total daily APM consumption increased from 278mg at Week Zero, to 311mg at Week Seven, to 383mg at Week 12.
- Quality of life: 20% increase in both groups.
- Appetite: Remained the same in both grops from baseline to Week 12, desire for sweets and carbohydrates decreased initially and then increased during active weight loss in both groups
- Vital signs: Reductions in pulse rate, diastolic blood pressure and systolic pressure occured in both groups
- Health events: Four adverse events; two unrelated to treatment; two experimental groups developed adverse effects related to diet.
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Aspartame group: Weight decrease (males) -23kg, (females) -16.5kg
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Control group: Weight decrease (males) -27kg, (females) -12.8kg.
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No statistically significant difference between the groups.
Author Conclusion:
- It is very unlikely that aspartame, when incorporated in a multidisciplinary weight loss program which includes a BDD, adversely effects weight loss or ability to comply with a hypocaloric diet.
- These data suggest there may be an advantage to adding aspartame to a weight loss program to sustain compliance, particulary after six weeks.
- By adding sweetness without calories, the variety and palatability of the diet are increased.
- A larger outpatient clincial study is needed to test findings.
- Data suggest that the hedonic component of satiety can be exploited with a modest intake of aspartame to achieve compliance to a hypocaloric diet program that includes desserts and sweets.
Funding Source:
Government: | NIH | ||
Industry: |
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University/Hospital: | New England Deaconess Hospital | ||
Not-for-profit |
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Reviewer Comments:
- This was a good study, but with weak statistical parameters.
- Overall, no difference between the groups.
- Products were mainly milk products, drinks and sweeteners.
Quality Criteria Checklist: Primary Research
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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? | 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? | 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? | No | |
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? | No | |
8.1. | Were statistical analyses adequately described and the results reported appropriately? | No | |
8.2. | Were correct statistical tests used and assumptions of test not violated? | No | |
8.3. | Were statistics reported with levels of significance and/or confidence intervals? | No | |
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)? | No | |
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? | 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? | No | |
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 | |