EAL

DF: Obesity (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

The purpose of this 14-month study was to investigate the effects of fiber supplements on maintenance of recent weight loss, blood lipids, and blood pressure in obese females.

Inclusion Criteria:

Obese females
No other inclusion criteria are provided.

Exclusion Criteria:

Not described

Description of Study Protocol:

Recruitment

Not described

Design

Randomized controlled trial

Blinding used

None

Intervention

Phase 1 Very Low Calorie Diet (VLCD):

All subjects were required to successfully complete a two month VLCD.
VLCD = 2MJ/d.

Phase 2 Fiber supplementation:

Female subjects randomized into the 14-month Phase 2 of this study must have lost of >5 kg of body weight during the two month VLCD phase
Subjects were randomly assigned to a fiber supplemented group or a non-treatment group. The specific randomization procedures are not described.
Intervention group:
- 20 grams of fiber supplements composed of enzymatically modified guar gum
- 10 gm of fiber supplement in the afternoon and 10 grams in the evening by dissolving the supplements in liquid such as water or juice.
Non-Intervention group:
- No placebo for the non-treatment group was used.

Statistical Analysis

Two-way ANOVA for repeated measures were used to study treatment effects and difference over time
Calculated percent changes were used to correct for differences in initial level of the parameters at the start of the experiment
Statistical significance was set at P<0.05.

Data Collection Summary:

Timing of Measurements

Exams to assess the dependent variables were conducted after an overnight fast at zero, two, four, 10 and 16 months.

Dependent Variables

Biological variables

Fasting blood samples collected using standardized techniques and analyzed for glucose, insulin, total cholesterol, HDL, LDL, apoprotein–A1, apoprotein-B, and lipoprotein(a)
Systolic and diastolic blood pressure (procedures not specified).

Anthropometric variables

Body weight, height and waist-hip ratio (procedures not specified)
Body composition measured using the deuterium dilution technique.

Independent Variables

20 grams of fiber per day, provided in two sachets of 10 grams. Fiber compliance was assessed by questionnaires and counts of returned sachets.

Control Variables

Baseline values were accounted for by using percent change differences in the analyses.

Dietary intake

Three day food diaries were recorded at all five time points of the study. The diaries were analyzed with the Dutch food tables and he accessory computer program.

Other Variables

Eating behavior

The Three Factor eating behavior was completed after each test day (the three factors included a restraint score, emotional/control score and hunger related score)
The Herman and Polivy questionnaire was used to check body weight fluctuations.

Description of Actual Data Sample:

Initial N:

48 obese females started the VLCD diet
41 subjects completed the diet
- The seven drop-outs were unable to follow the strict VLCD regimen. Two additional subjects who lost <5 kg were also excluded. This left 39 subjects randomized into this weight maintenance phase, of which eight dropped out for various documented reasons.

Attrition (final N): 31 subjects

Age: Average age for all groups 41.4+7.4 years

Ethnicity: Not provided

Anthropometrics: There were no significant differences among groups for all baseline characteristics including age, body weight, height, BMI, systolic blood pressure, diastolic blood pressure, waist to hip ratio, and percent body fat.

Location: Unlcear [IRB from Masstricht University ?(Netherlands)]

Summary of Results:

Compliance of fiber intake

Although not originally part of the study design, questionnaires and fiber sachet counts related to supplemented fiber compliance were used to classify two fiber subgroups for analysis:

Group A (n=10) consumed more than 80% of the supplemented fiber
Group B (n=10) consumed between 50-80% of supplemented fiber
Control group (n=11) was the control group.

Weight regain

On average the % of weight regain at 16 months was:

Group A: 65% (+65%)
Group B: 123% (+63%)
Control group: 61% (+66%).

Differences in these relapse rates were almost significant (F(2, 30) = 2.029; P=0.07)

Body weight regain was higher for Group B when compared to Group A and Control Group at four months and (P=0.08) and at 10 months (P<0.05).

At the end of the 16 months, Group A and Group C had a lower body weight when compared to baseline (P=0.09). Body weight gain for Group B was equal to baseline.

Anthropometric data at 0 and 16 months

Variables	Month 0 Mean (SD)	Month 16 Mean (SD)
Body weight (kg)
A	89.8 (12.0)	85.6 (13.1)*
B	87.0 (5.9)	88.4 (9.8)*
Control	89.4 (12.6)	85.0 (12.0)*
BMI (kg/m2)
A	33.9 (2.8)	32.3 (3.7)*
B	32.7 (3.6)	33.2 (5.0)*
Control	32.9 (4.7)	31.4 (5.1)*
Body fat (%)
A	42.6 (4.4)	42.1 (3.3)*
B	43.6 (3.8)	44.6 (4.5)* ^(a)
Control	42.6 (4.5)	38.9 (5.1)*
Waist-hip ratio
A	0.85 (0.04)	0.82 (0.04)*
B	0.82 (0.06)	0.83 (0.05)*
Control	0.84 (0.06)	0.83 (0.04)*

*The differences over time (zero, two, four, 10, 16 months) were significant. (Comparisons to indicate which months are significantly different from one another are not provided)

^(a) The only between group differences were for group B and the control group (at week 14)

Biological Findings

No differences were found between groups for:

Blood pressure, glucose, insulin, total cholesterol, HDL, LDL, apoprotein–A1, apoprotein-B, and lipoprotein(a)

Dietary Intake

The mean energy intake levels of the three groups changed significantly over time from baseline to after the VLCD
Mean energy intake showed a tendency of differences in energy intake between groups (P=0.07). (Details on which groups were different are not provided).
At 16 months only group A showed a lower energy intake than the other two groups, but this was not significantly different (P=0.11).

Eating behavior

Restraint:
- At month 16 when from baseline, Group A showed significantly increased restraint scores and significantly lower hunger related scores
- These changes were not found for Group B and the Control Group
Changes in eating behavior characteristics over the whole study period were not related to compliance of fiber intake
When the whole group was studied, only the restraint score was significantly related to changes in body weight
When the groups were analyzed separately, a significant relationship was found in Group A between the among of weight change and the change in the emotional/control score.

Author Conclusion:

In the present study no effect of 20g of guar gum supplementation per day was found on long-term weight maintenance, blood pressure, blood cholesterol or any other relevant parameter investigated. The control group showed the same physiological changes as the fiber supplemented groups. Weight maintenance was even better achieved in the control group than in the fiber Group B.

The results of this study suggest that eating behavior, specifically changes in cognitive restraint score and emotional/control scores, are related to weight change.

Funding Source:

Industry:

Sandoze Nutrition (Sweden)

Pharmaceutical/Dietary Supplement Company:

Reviewer Comments:

The biggest limitation was the extremely small sample and lack of power calculation within the context of the null findings. Critical details are lacking on the recruitment, inclusion/exclusion criteria and the method of randomization. Although there was a comparison non-treatment group, lack of blinding and use of placebo was a weakness of the study design.

Strengths include the duration of the study, assessment of protocol compliance, and accounting for total energy intake.

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?		No
	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?	No
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	No
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
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%.)	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?		No
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	No
	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.)	No
	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?	Yes
	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?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	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?		No
	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)?	Yes
	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?	No
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