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
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
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.
- 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.
- 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:
- 86 volunteers were screened, of which 59 enrolled. Accrual began in December 1986 and was completed in March and April 1987.
- Participants were randomly assigned to control or experimental diets in a prospective parallel design.
- 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.
- 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.
Aspartame group: Weight decrease (males) -23kg, (females) -16.5kg
Control group: Weight decrease (males) -27kg, (females) -12.8kg.
No statistically significant difference between the groups.
- 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.
|University/Hospital:||New England Deaconess Hospital|
- 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
|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|
|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|