EAL

NNNS: Effect on Energy Balance (Weight) (2010)

Citation:

Study Design:

Class:

- 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.

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.

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:

NutraSweet Company

Food Company:

University/Hospital:

New England Deaconess Hospital

Not-for-profit

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
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