NC: Behavior Change Strategies (2007-2008)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To examine the usefulness of increasing therapist contact through phone calls and mailings to promote self-monitoring and improve weight control during the high risk Christmas-to-New-Year holiday season.
Inclusion Criteria:

1.) Involved in a cognitive-behavioral treatment program for at least 1 month

2.) Identified by their therapists as self-monitoring less than 100% of the time during the last 6 months

3.) Available to be reached by phone during the 2-week intervention period

4.) Not currently on an Optifast regimen

Exclusion Criteria:
Not stated
Description of Study Protocol:

Recruitment:  Recruited from two long-term cognitive-behavioral treatment programs for obesity. 

Design:  Subjects were randomized into a self-monitoring intervention or comparison group.

Blinding used (if applicable):  Not applicable

Intervention (if applicable):  Participants self-monitored for a total of 8 weeks:  3 weeks before the holiday period (preholiday), 2 weeks during the holiday period (1 week before Christmas through New Year's), and 3 weeks after the holiday period (postholiday).  All participants continued participating in a weekly cognitive-behavioral treatment program throughout the study.  Participants in the intervention group, however, also received daily mailings and 1-2 phone calls per week during the two-week period between Christmas and New Year's reminding them to self-monitor.

Statistical Analysis:  A repeated measures of analysis of variance (ANOVA) was computed with one between-subjects factor (group-intervention, comparison) and one within-subjects factor (time; preholiday, holiday, postholiday). 


Data Collection Summary:

Timing of Measurements:  Weight and consistency of self-monitoring was measured at each weekly meeting. 

Dependent Variables

  • weight
  • consistency of self-monitoring; defined as the average weekly percentage of days during which self-monitoring was complete. 

Independent Variables

    Therapist contact

Control Variables-Not applicable


Description of Actual Data Sample:

Initial N: 57 (16 males, 41 females)

Attrition (final N): Not reported

Age: mean age:  44.5 (SD=10.0)

Ethnicity: Caucasion:  53 (93%)

                African American: 3 (5.3%)

                Hispanic: 1 (1.8%)

Other relevant demographics:

Single:  35%

Married:  53%

Separated, divorced, or widowed:  12%.


Completed only high school:  9%

Attended some college:  14%

College degree:  35%

Graduate degree:  39%

Reported education as 'other':  4%

Participants had participated in the treatment programs for an average of 17.1 months (range = 1 to 120).


Participants' mean weight at the beginning of this study was 223.2 lbs (SD=55.6) with an average BMI of 35.5 (SD=7.3).   

Participants had lost an average of 33.2 lbs (SD=27.3, range = -.6 to -122.0 lbs) in the program when this study began.

Location: Not stated.


Summary of Results:


The intervention group lost more weight cumulatively from week 1 (baseline), group F (7, 48) =4.60,  p=.036.

Cumulative weight losses over the 8 weeks were intervention M = -2.0 (SD=5.4) versus comparison M =2.0 (SD=7.7).

The intervention group (M = -0.2, SD = 0.6) averaged greater weekly weight losses compared with the comparison group (M = 0.2, SD=0.9), group F (1,55) = 5.24, p=.026.  Overall, participants showed average weekly weight losses at both the preholiday (M =0.3, SD=1.4) and postholiday (M = -0.1, SD=1.9), producing a significant effect for time, F(2, 110) = 6.95, p=.001

Newman-Keuls multiple comparisons revealed that the particpants gained more weight druing the holiday period than the preholiday and postholiday phases (p<.01)

The intervention group managed their weight significantly better than the comparison group over the entire 8 weeks, t(55) =2.10, p=.04, and during the holidays (intervention M =0.0, SD =1.5; comparison M = 1.2, SD =2.0), t(55) =2.41, p=.019.


Participants monitored much more consistently during the preholiday (M =75.7%, SD =29.5) than during both the holiday (M = 64.0%, SD =37.2) and postholiday (M = 60.9%, SD =34.9) phases, F (2, 110) = 9.19, p<.0001.

The intervention group self-monitored more consistently than the comparison group only during the holidays (intervention M =75.5%, SD =31.0; comparison M = 53.0%, SD=40.0, t(55) = -2.38. p=.021.

Other Findings


Author Conclusion:

The intervention group self-monitored more consistently and managed their weight better than the comparison group throughout the holiday weeks.  The intervention group also lost more weight during the 8 weeks of the study.  A decrease in weight was significantly associated with an increase in monitoring.  The effectiveness of the intervention was particularly noteworthy because all participants were experienced weight controllers, averaging 17 months in weekly treatment at the onset of the study. 

The comparison group averaged a weight gain of over a pound per week during the holidays.

It is not know which component of the intervention contributed to improvements in self-monitoring and weight control compared with the comparison group.  The phone calls from therapists, the content of the phone calls, or some aspects of the mailings all may have contributed to the beneficial effects. 

Evaluation of consistency of self-monitoring may identify those clients who may benefit from additional contact, especially during the high-risk periods.


Funding Source:
Reviewer Comments:

Small sample size.  Wonder how this intervention would work for subjects not previously participating in a weight loss program, although the author feels new weight controllers may experience an enhanced effect from the additional contact and attention (don't think that is a bad effect).

Author does not state how many subjects were in the intervention group and how many were in the comparison group.

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? ???
  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? ???
  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? ???
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? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? ???
  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.) ???
  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? ???
  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? ???
  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? No
  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? Yes
  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)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  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? 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? ???
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes