NC: Behavior Change Strategies (2007-2008)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To compare the use of meal replacements in an established university-based weight loss clinic and a primary care physician practice and to evaluate the potential health benefits of sustained weight loss for specific chronic disease risk factors associated with the moderately overweight and obese.
Inclusion Criteria:
Overweight or obese premenopausal women aged 25 - 50 years with BMI between 25 - 35.
Exclusion Criteria:
Current chronic or or psychological disease, abnormal serum laboratory values of clinical significance, or current hormone replacement therapies.  Women were also excluded who were pregnant, planning to become pregnant, lactating, or planning to move out of the area within the following year.
Description of Study Protocol:


Respondents to media announcements and flyers distributed in the local community.


Randomized trial.

Blinding used (if applicable)

No blinding used.

Intervention (if applicable)

Randomly assigned to 3 different traditional lifestyle-based groups for 1 year:  dietitian-led group intervention (1 hour per session), dietitian-led group intervention (1 hour per session) incorporating meal replacements, or primary care office intervention incorporating meal replacements with individual physician and nurse visits (10-15 minutes per visit). 

Statistical Analysis

Weight change was examined by 1-way ANOVA with subsequent a priori analyses using contrasts for completers and for all subjects by intent to treat (last observation carried forward).  Percentage of weight loss from initial body weight, total cholesterol level and blood pressure were recorded into dichotomous variables.  The mean differences for these variables were assessed with independent t tests.

Data Collection Summary:

Timing of Measurements

Eligible women were scheduled for a 1-hour clinic assessment to determine their fasting serum chemistry, lipid, insulin, and glucose values, weight, height, BMI, waist circumference, body fat percentage, REE, blood pressure, dieting history, eating and activity habits, and psychosocial status.  All subjects attended 26 sessions over 1 year and received instruction manuals based on Lifestyle, Exercise, Attitude, Relationships and Nutrition (LEARN) Program for Weight Control.  Weight, height, waist circumference, skinfolds, REE and blood pressure taken at 1 year.

Dependent Variables

  • Fasting blood used for serum lipid levels (cholesterol, HDL and LDL cholesterol, triglycerides) and glucose and insulin.  Blood values analyzed by standard methods at statewide certified clinical laboratory
  • Weight measurements to nearest 0.1 kg taken using calibrated balance beam scale with patients dressed in light clothing without shoes
  • Height to nearest 0.1 cm taken using wall mounted stadiometer
  • Waist circumference measured at narrowest part of torso to nearest 0.5 cm using nonstretchable tape measure
  • Skinfolds (triceps, thigh and superior iliac crest) measured to nearest 0.1 mm with Lange caliper
  • 24-hour REE estimated from 20-minute respiratory sample in fasting subjects using ventilated canopy hood by indirect calorimetry
  • Blood pressure measured on right arm using mercury-column manometer to nearest mm Hg after fasting subject had been seated quietly for 5 minutes

Independent Variables

  • Lifestyle-based interventions:  Traditional dietitian-led intervention group, Traditional dietitian-led intervention group incorporating 2 meal replacements with Slim Fast shakes or bars (220 kcal each), or Primary care office intervention incorporating 2 meal replacements with individual physician and nurse visits.  For all groups, diet target was 1200 kcal/day.  Activity instruction involved pedometers.  Subjects completed homework assignments recommending food intake and activity level records. 

Control Variables


Description of Actual Data Sample:

Initial N: 113 women

Attrition (final N):  74 women (65% completion).  Retention rates among 3 treatment groups were similar.

Age:  mean age 41.4 +/- 4.7 years 

Ethnicity:  Not mentioned. 

Other relevant demographics:   

Anthropometrics:  There were no significant differences among the baseline parameters by treatment group.

Location:  Nevada 


Summary of Results:


Dietitian-led only (n=23) Dietitian-led + MR (n=26) Primary care office + MR (n=25)

All subjects (n=74)

Actual weight change (kg) -3.4 +/- 5.4 -7.7 +/- 7.8 -3.5 +/- 5.5 -5.0 +/- 6.6
% weight change -4.1 +/- 6.4

-9.1 +/- 8.9

-4.3 +/- 6.5

-5.9 +/- 7.6


-1.0 +/- 2.0

-2.5 +/- 2.7

-1.3 +/- 2.0

-1.6 +/- 2.3

Other Findings

Subjects in the dietitian-led intervention with meal replacements (n=26) lost significantly more weight than those in the other groups at 1 year (7.7 +/- 7.8 kg, 9.1 +/- 8.9% initial body weight vs 3.4 +/- 5.4 kg, 4.1 +/- 6.4% initial body weight in the dietitian-led intervention only and 3.5 +/- 5.5 kg, 4.3 +/- 6.5% initial body weight in the primary care office intervention with meal replacements, P = 0.03). 

The primary care office intervention using meal replacements was as effective as the traditional dietitian-led group intervention not using meal replacements (4.3 +/- 6.5% weight loss vs 4.1 +/- 6.4%, respectively).

Comparison of the dietitian-led groups showed that women using meal replacements maintained a significantly greater weight loss (9.1 +/- 8.9% vs 4.1 +/- 6.4%, P = 0.03).

Analysis across groups showed that weight loss of 5 - 10% was associated with significant (P = 0.01) reduction in percentage of body fat, BMI, waist circumference, REE, insulin level, total cholesterol level, and LDL cholesterol levels.

Weight loss of 10% or greater was associated with additional significant (P = 0.05) improvements in blood pressure and triglyceride level. 

Author Conclusion:
A traditional lifestyle intervention using meal replacements can be effective for weight control and reduction in risk of chronic disease in the physician's office as well as in the dietitian-led group setting.  This study demonstrates that weight loss can be achieved using lifestyle counseling incorporating meal-replacement strategies.  In addition, meal replacements can improve the magnitude of weight loss in a traditional dietitian-led group intervention that includes multiple sessions to promote changes in food selection, suggestions for increasing physical activity, and appropriate behavior change.
Funding Source:
Food Company:
Reviewer Comments:
Large dropout rate after 1 year.
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? Yes
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.) 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? 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? ???
  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? 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)? 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? 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? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes