NC: Behavior Change Strategies (2007-2008)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of this study was to: 

  • determine which weight management program components were perceived as useful by  participants.
  • determine strategies still being used by individuals who were successful in losing weight and maintaining weight loss. 
Inclusion Criteria:

Individuals ages 30-54 years old who had:

  • high normal blood pressure (diastolic 89-89 without antihypertensive medication)
  • mild obesity (115-160% of IBW)
  • overall good health

and participated in the weight management intervention and completed the study questionnaire.

Exclusion Criteria:

Individuals from the weight management intervention program who did not complete the study questionnaire (no other exclusion information provided).

Description of Study Protocol:


Limited information provided. Participants obtained from 308 subjects participating in a TOHP (Trials of Hypertension Prevention) Phase I Study who were randomly assigned to the weight/exercise intervention program. 


At the end of the 18-month program, 281 (of 308) participants completed a 21-item questionnaire about lifestyle changes, perceived success of weight management, and usefulness of major intervention components. Participants were divided into 3 groups based on intervention results and groups were compared on perceptions of program's effectiveness and components being used at end of program. Adherance barriers were also examined.

Groups were defined as:  

  • "successful" (lost >10 lb. and had not regained >50% of weight loss by program's end)
  • "relapsed" (lost >10 lb. but regained >50% or more of weight lost)
  • "unsuccessful" (did not lose at least 10 lb. during intervention)


Blinding used (if applicable) 

  1. Questionnaires were administered in a standardized fashion at the final data collection visit by data collectors who were blinded to the participants' intervention assignments and who were not associated with the weight loss intervention. 
  2. Weights were measured during clinic visits by independent certified personnel who were blinded to intervention status.

Intervention (if applicable)

Intervention was a program of dietary change, behavior modification, and increased exercise conducted by teams of centrally trained registered dietitians, exercise physiologists, and psychologists. Focus was on self-management of energy intake, exersice, and individually determined behavior goals.  Participants developed a regular exercise program and over an 18-month period attended 14 weekly 90-minute group sessions followed by an extended intervention phase of at least monthly contact to include group meetings, weekly weigh-ins, or individual counseling. Study goal was 1-2 lb. weight loss/week (minimum 10 lb. weight loss) to be mainained for the 18-month study duration.

Statistical Analysis

Chi-square analyses were conducted to evaluate the statistical signficance of group differences. 

Data Collection Summary:

Timing of Measurements   Questionnaire was administered at the final data collection period of the 18-month weight management program.   

Dependent Variables

         Weight management program outcome (successful, relapsed, unsuccessful) (which itself was determined by weight lost and amount regained during the intervention).

Independent Variables

         Participants' evaluation of program component usefulness  

         Program components still being used at end of the 18-month program        

Control Variables None (though age, gender, race, education, marital status were considered)  

Description of Actual Data Sample:

Initial N: 308 subjects (224 men and 84 women) who were randomly assigned to the weight loss/exercise intervention program of the TOHP Phase I Study (1987-1991)

Attrition (final N): 281 (91%) of 308 subjects completed the questionnaire. Of the 281, 204 (73%) were male and 77 (27%) were female  

Age: Mean age was 42.9 years with no significant difference between genders

Ethnicity:  Not indicated

Other relevant demographics:

Race: Of the 281 subjects, 82% were White

Marital Status: 81% were married or living with a partner

Education: 85% of subjects had some college   

Anthropometrics (e.g., were groups same or different on important measures)

Weight loss at end of program averaged:  

  • 19.9 + 11.0 lb in the "successful" group
  • 4.4 + 6.1 lb in the "relapsed" group

The "unsuccessful" group averaged a 1.9 + 5.6 lb weight gain   


6 clinical centers that were partipating in a collaborative, multicenter clinical trial desiged to test the effects of lifestyle changes on development of age-related increases in blood pressure. 

Summary of Results:
  1. Demographic characteristics associated with program success included being White (P<0.001), being married/living with partner (P<0.005), and being male (P<0.005).
  2. 60% of participants indicated periodic individual meetings to be a very helpful adjunct to the primarily group approach weight management intervention.
  3. Program components reported as very useful by >50% of the  participants were the following: nutrition topics (77%), calorie counting (77%), weekly weigh-ins/group contacts (75%), written feedback on food record (55%), exercise topics (53%), behavior topics (53%), and sharing progress/graphs (51%)
  4. Few participants found exercising in a group useful. Successful participants were significantly more likely to consider weekly weigh-ins/group contact (P<0.001) and calorie counting (P<0.05) as useful. Older participants were more likely to attend regularly scheduled0 program sessions. 
  5. Exercise was the behavior component most commonly still being used by participants at the end of the 18-month intervention. "Successful" participants were significantly more likely to report they still exercised regularly (P<0.001), still incorporated exercise into their regular daily activities (P<0.05), still graphed exercise (P<0.05), and had continual attendance at intervention meetings in the extended phase of program (P<0.001)  
  6. Among factors identified as barriers or obstacles to behavior change, "unsuccessful" participants were significantly more likely to report a lack of motivation from the outset (P<0.01), insufficient time (P<0.05), and frustration caused by insufficient results for their efforts (P<0.001).
  7. There were no between-group differences for eating out/travel and stress. Women were more likely to report stress and frustration because of disappointing results.  
Author Conclusion:
  1. Intervention session attendance and continued adherance to program components were related to long-term success, and older participants were more likely to attend the regularly scheduled sessions.
  2. "Successful" participants were more likely to endorse self-regulatory activities (e.g., exercise, self-monitoring of food intake, weekly weighing) as useful. Few participants reported exercising in groups as useful.
  3. Involvement in a regular personal exercise program and incorporation of exercise into daily activities were rated highest among program components still being used by participants at the end of the intervention.
  4. Interventionists should aim to find flexible and creative ways to maintain contact with participants, develop better techniques for self-monitoring, obtain skills to recognize frustration and offer timely support, and help participants develop problem-solving skills.
  5. Dietitians may need to collaborate with other professionals and/or seek out additional training in order to develop and implement these interventions.   
Funding Source:
Kaiser Permanente
University/Hospital: Saint Louis University, VA Medical Center, University of California at Davis
Reviewer Comments:
  1. The authors refer at times to this being an 18-month follow up; this is confusing language since the  the data was actually collected at the end of  the 18-month intervention and not 18 months after program ended.    
  2. Mean age listed for unsuccessful participants (Table 1, page 67) does not appear to be correct (mean age listed is 2.6 +5.9 years).
  3. Not much specific information is provided about program components (e.g., dietary intervention, behavioral strategies, etc.), though article gives reference for more detailed information.
  4. It's unclear why only 281 of the original 308 subjects in the study completed the questionnaire. Did the remainder drop out? refuse to complete the questionnaire even though they finished the program?   
  5. Subjects were predominantly male, White, and fairly well educated so there are some limits to generalizablity.  
  6. Unique characteristic of study is that it assessed usefulness of the program components from the participants' perspective.
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? ???
  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? No
3. Were study groups comparable? No
  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? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  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? Yes
  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? ???
  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? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  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? Yes
  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? ???
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? ???
  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? N/A
  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? N/A
  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)? No
  8.6. Was clinical significance as well as statistical significance reported? Yes
  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? ???
  10.2. Was the study free from apparent conflict of interest? ???