Pediatric Weight Management

PWM: Prescribed Diet Plan and Nutrition Education (2006)


Epstein LH, Valoski AM, Vara LS, McCurley J, Wisniewski L, Kalarchian MA, Klein KR, Shrager LR. Effects of decreasing sedentary behavior and increasing activity on weight change in obese children.  Health Psychol 1995;14:109-15.

PubMed ID: 7789345
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To compare the effects of reinforcing children for increasing physical activity, reducing time spent being sedentary, and the combination of both on child weight control.
Inclusion Criteria:
  1. Child 20-100% OW (based on Hamill, 1977 standards)
  2. Neither parent >100% OW (based on 1983 Metropolitan Life tables)
  3. 1 parent willing to attend treatment meetings
  4. No family member on alternative weight control program
  5. No child/parent having current psychiatric problems
  6. No medical problems that would prevent exercise
Exclusion Criteria:
None specified
Description of Study Protocol:

Family Recruitment

Recruited through radio announcements, TV commercials, posters and referrals by physicians & school nurses in 2 approximately equal cohorts; cohorts provided treatment at same season of sequential years.

Family Randomization (method not described) to the following groups)

  1. Reinforcing  sedentary activity
  2. Reinforcing  physical activity
  3. Both


  • Meetings – Weekly meetings for 4 mo + 2 monthly meetings thereafter; parents and children weighed and counseled together by a therapist and then attended separate group meetings for parents or children.
  • Diet – ‘Traffic Light Diet’ to reduce energy intake of children and OW parents to 1000-1200 kcals/d and limit ‘red foods’ to <7/wk; no reduction in energy intake for non-OW parents, but were instructed to limit ‘red foods’ to <7/wk.
  • Physical activity – written manuals on effects of physical activity & inactivity + reinforcement for activities
    • Targeted activities:
      • Sedentary activities to  – watching TV, playing computer games, imaginative play, talking on phone, playing board games (academically relevant sedentary behaviors, such as homework or school-related reading, were not targeted for reduction)
      • Physical activities to  - any except those done routinely as a required part of work or school day
      • Reinforcement system: 5-levels
      • Sedentary activities – 5 hr incremental decreases from <=35 hr/wk (Level 1) to a <=15 hr/wk (Level 5)
      • Physical activities – 30 point incremental increases from 30 points/wk (Level 1) to 150 points/wk (Level 5) [10 points = 100-calories expenditure for a 150 lb person)
    • Reinforcement schedule:
      • Parents & children advanced independently
      • Advanced one level at a time
      • After met Level 5 criteria, required to maintain activity changes throughout remainder of treatment program to earn contract rewards
      • Weight goal to either lose 3 lbs or maintain weight for 3-week intervals (depending on whether reached IBW) added to Level 5 in order to earn contract reward
  • Behavioral principles
    • Personalized system of instruction  - manuals divided into modules; each module contained information, practice situation, and a reading quiz with answers and a test
    • Self-monitoring – weight, ‘habit book’ to record food intake and time spent on physical and sedentary activities
    • Stimulus control – modeling, changing environment
    • Reinforcement – family praise, reciprocal contracting

Statistical Analysis

  • Mixed analysis of variance - 2 between factors (group and cohort) and time as the within variable; no differences by cohort so cohorts collapsed for further analyses
  • General linear models – to compare changes over time (0, 4 and 12 mo on body comp & fitness data, 0 & 4 mo on questionnaire data, and last 2 weeks of treatment for compliance data)
  • Post hoc tests – exact tests not specified
  • Outliers – 4 removed from analysis for intake only because unrealistically low and statistically deviant
Data Collection Summary:

Dependent Variables

  • % OW (measured height & weight)
  • % Body fat (BIA)
  • WHR
  • Fitness (physical work capacity by bicycle ergometer)
  • Activity preference (questionnaire with activity defined as sedentary <=2.0 METS, moderate intensity 3-4.9 METS, high intensity >=5.0 METS and using computer-based lab-choice paradigm in which children earn points to have different activities accessible [Note: could not fully understand from description provided])
  • Energy intake (‘habit books’ for last 2 weeks of treatment)


Independent Variables

  • decreased sedentary activity
  • increased physical activity
  • or both

Control Variables


Description of Actual Data Sample:

Original Sample: 92 families screened, 61 entered treatment, 27% of children were male, 8-12 years old


  • 2 dropped out during treatment +
  • 2 refused follow-up +
  • 1 child got leg injury (unrelated to study) +
  • 1 parent died during study

Final Sample:

  • 55 families, 55 children
  • Child age mean 10.1 years

Location:  Buffalo, NY?

Duration:  12 mo:  6 mo treatment + 6 mo follow-up

Race/Ethnicity:  96% White

SES:  Hollinghead 4-factor index = 48.7 (equivalent to medium-level business, minor professional & technical professions)

Summary of Results:


  • Children - 51.8% OW, 33.2% body fat, 0.94 WHR
  • Parents – moms 19.8% OW, dads 33.4% OW; % with at least 1 obese parents =82%, 68% and 74% in groups 1-3, respectively
  • No differences on any child or adult measure between groups

Percent Overweight:

  • Significant between-group differences in rate of change over time (F(4,102) = 3.14, p=.026)
  • At 4 mo – decrease sedentary group had a greater decrease in % overweight than the increase physical activity group (p<.05)
  • At 12 mo – decrease sedentary group had a greater decrease in % overweight than both the increase physical activity group and combined group (p<.05)

Percent Body fat:

  • Significant between-group differences in rate of change over time (F(4,94) = 2.67, p=.037)
  • At 4 mo – decrease sedentary group had a greater decrease in % body fat than the increase physical activity group (p<.05)
  • At 12 mo – decrease sedentary group had a greater decrease in % body fat than both the increase physical activity group and combined group (p<.05)  (p<.05)


  • Significant change over time (F(2,80) = 4.79, p=.011) with no between-group differences (normally decrease from ages 1-17)


  • Significant increase over time (F(2,80) = 4.79, p=.011) with no between-group differences
  • Baseline = 59.5 watts, 4 mo = 74.9 watts, 12 mo = 63.3 watts

Preference for PA:

  • For high intensity activity - Significant change over time (F(2,49) = 4.53, p=.02)
  • At 4 mo – decrease sedentary group  > increase physical activity group (p=.004)
  • For moderate intensity activity – no between-group change over time
  • For sedentary activity no between group change over time

Energy intake:

  • Significantly different between groups (F(2,42) = 9.36, p<.001)
  • At 4 mo – increase physical activity group (1124 kcal) > decrease sedentary group (984 kcal) & combined group (973 kcal)
  • No significant differences in compliance using standardized compliance measures (?)
Author Conclusion:

These results support the goal of reducing time spend in sedentary activities to improve weight loss.

One possible mechanism for the differences is that children reinforced for reducing sedentary behaviors substitute higher expenditure activities, thereby increasing negative energy balance.  The significantly greater increase in liking for high-intensity activity in the sedentary group is consistent with this hypothesis.  Though direct measures of activity are lacking, the significant and equivalent improvements in fitness provide objective evidence that children in each group increased their activity.

Reinforcing a reduction in specific sedentary behaviors provides children the opportunity to choose how to allocate newly available time.  The opportunity to choose among alternative is reinforcing.

The multiple changes required for the combined group may have made it more difficult to make the individual exercise and sedentary changes, thereby diluting the effects of the sedentary intervention.

Funding Source:
Government: NIH
Reviewer Comments:


  • Thorough description of study protocol and subjects.


  • No comparison group without any activity program (diet only),
  • unclear sample size per group,
  • no control for potential confounders,
  • no blinding of measurements.
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? ???
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) ???
  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.) ???
  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? ???
  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.) ???
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? ???
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? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? ???
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? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? ???
  5.5. In diagnostic study, were test results blinded to patient history and other test results? ???
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? ???
  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? ???
  6.6. Were extra or unplanned treatments described? ???
  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? ???
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? 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? 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? ???
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