MNT: Weight Management (2015)
Collinson A, Lindley R, Campbell A, Waters I, Lindley T, Wallace A. An evaluation of an Internet-based approach to weight loss with low glycaemic load principles. J Hum Nutr Diet. 2011; 24:192-195.
PubMed ID: 21843154
- BMI 28kg/m2 or more
- Approval from a medical practitioner.
Recruitment
Local newspaper used to recruit participants.
Design
- Pre-experimental before and after design
- No control group
- Measures were taken at baseline and six months later.
Intervention
Participants received standardized online instruction to consume an energy-restricted diet incorporating low GL foods. The New Zealand Heart Foundation food pyramid served as a guide for recommendations and participants were encouraged to consume two servings of beans and legumes and one serving of protein daily. Physical activity was encouraged. A bi-weekly chat room with a dietitian and peers was provided and cognitive behavioral strategies such as stimulus control, problem solving, goal setting and coping with negative thoughts were incorporated into the program.
Statistical Analysis
- A paired T-test was used to assess weight change from baseline to six months
- Mann-Whitney U and chi square tests were used to assess differences in clinically significant weight loss (more than 5% of their body weight at baseline) and use of the chat room, whether they self-reported their weight loss, whether they had greater self-reported energy levels and better exercise scores
- Wilcoxon-signed rank was used to compare differences in the amount of food groups within participants baseline to six months.
Timing of Measurements
Baseline to six months.
Dependent Variables
- Weight loss: Height, weight and waist circumference were measured at baseline and six months by a trained researcher
- Food intake: Self-reported using online food records to report foods and serving sizes
- Energy levels, satiety levels and exercise habits: Also self-reported online at baseline and six months.
Independent Variables
A standardized online instruction incorporating low GL foods and cognitive behavioral strategies as explained above.
- Initial N: N=103 participants (71 female, 32 male)
- Attrition (final N): N=70 participants (47 female, 23 males); 32% attrition
- Age: Mean (SD) age was 45.5 years (11.4 years) of final 70 participants.
Anthropometrics
- BMI categories:
- 28 to 29.9: N=7 (10%)
- 30 to 34.9: N=28 (40%)
- 35 to 39.9: N=27 (39%)
- More than 40: N=8 (11%).
- Mean (SD) waist circumference: 109.6 (13.8)
- No statistical differences in baseline characteristics at baseline between total sample and those who completed the study.
Location
Christchurch, New Zealand.
Key Findings
Variable | Baseline Mean (SD) |
Six Months Mean (SD) |
Change Mean (CI) |
P-value |
Weight (kg) | 99.7 (15.6) | 96.2 (15.9) | 3.5 (2.3 to 4.7) | 0.001 |
BMI | 35.5 (4.8) | 34.2 (5.1) | 1.2 (0.8 to 1.7) | 0.001 |
Waist circumference (cm) | 109.6 (13.8) | 104.8 (13.0) | 4.8 (2.8 to 6.8) | 0.001 |
Other Findings
- After six months:
- A total of 51 (73%) lost weight
- A total of 25 (36%) lost a clinically significant amount (more than 5%)
- A total of 19 (27%) gained weight.
- A total of 35 (50%) used the chat room and lost more weight than non-users (4.8kg vs. 2.2kg, P=0.036)
- Participants who lost a clinically significant amount of weight were more likely to enter self-reported weights (P=0.014), were more likely to use the chat room (P=0.037) and reported greater energy levels (P=0.035) than those not losing as much weight
- No differences in reported exercise activity was found
- A total of 90% made at least one positive dietary change; 74% and 47% increased fruit and vegetables, respectively. Legume intake significantly increased in 79% of participants (P<0.001) and 39% decreased their meat intake (P<0.001).
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Not-for-profit |
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- Large dropout rate
- No control group
- Many potential confounders
- Self-report nature of outcome variables.
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? | 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? | Yes | |
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? | No | |
3. | Were study groups comparable? | N/A | |
3.1. | Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) | N/A | |
3.2. | Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? | N/A | |
3.3. | Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) | No | |
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? | No | |
4.1. | Were follow-up methods described and the same for all groups? | No | |
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? | No | |
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? | N/A | |
5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | N/A | |
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.) | N/A | |
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? | ??? | |
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? | N/A | |
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)? | 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? | No | |
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 | |